Substantia. An International Journal of the History of Chemistry 5(1) Suppl.: 59-75, 2021

Firenze University Press 
www.fupress.com/substantia

ISSN 2532-3997 (online) | DOI: 10.36253/Substantia-1278

Citation: S. Dominici (2021) A Man with a 
Master Plan: Steno’s Observations on 
Earth’s History. Substantia 5(1) Suppl.: 
59-75. doi: 10.36253/Substantia-1278

Copyright: © 2021 S. Dominici. This is 
an open access, peer-reviewed article 
published by Firenze University Press 
(http://www.fupress.com/substantia) 
and distributed under the terms of the 
Creative Commons Attribution License, 
which permits unrestricted use, distri-
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Competing Interests: The Author(s) 
declare(s) no conflict of interest.

A Man with a Master Plan: Steno’s Observations 
on Earth’s History

Stefano Dominici

Museo di Storia Naturale, Università di Firenze, Via La Pira 4, Firenze, Italy
E-mail: stefano.dominici@unifi.it

Abstract. We present specific sources, including specimens of the Medicean cabinet 
and geological outcrops in Tuscany, probably used by Nicolaus Steno to build a the-
ory on the origin of organic fossils, crystals and sedimentary strata, in order to con-
struct the history of the Earth based on universal geometric principles. Phenomena he 
observed in Tuscany and in preceding travels were revealing a sequence of events con-
sistent with the biblical account. We propose that he devised his method to reconstruct 
a chronology of primordial events to demonstrate the historicity of the biblical creation 
in contrast to unorthodox thinking. This had been spreading in philosophical circles 
of northern Europe since the 1650s, circles frequented by Steno before his arrival in 
Tuscany in 1666. Steno knew in advance what places to visit to find fossils, from lit-
erature such as Michele Mercati’s Metallotheca. This was a manuscript owned by the 
Florentine Carlo Dati, whom Steno probably heard about while in Paris in 1664-1665. 
In Tuscany he soon formed a tight interaction on matters regarding the interpretation 
of fossils with the local community of learned men. These included Giovanni Alfon-
so Borelli who was asked by Prince Leopoldo de’ Medici to provide Steno with fos-
sils from Sicily and Malta. Steno’s theory and scale-independent, geometrical method 
of inquiry of geological objects found in Tuscany is hinted at in his Canis Carchariae 
Dissectum Caput, a geological essay completed in a few months in 1666. The theory 
was published in its most complete form in the so-called Prodromus of 1669. In both 
works he demonstrated that fossils in younger strata in the Tuscan hills, such as shark 
teeth and molluscan shells, have an origin analogous to solids which living animals 
form. In both essays he explicitly related the deposition of strata with marine fossils 
to the biblical flood, an idea foreshadowed in “Chaos,” his oldest known manuscript of 
1659, when he was a student in Copenhagen. He found no fossils in older sandstones 
of the Apennines and understood those strata to have formed before the creation of 
life. These discoveries and other observations he made in Tuscany were, for Steno, the 
final proof that natural philosophy and biblical revelation disclose in synergy the mys-
teries of God’s creation.

Keywords: Nicolaus Steno, Meaning of Fossils, Natural Philosophy, Accademia del 
Cimento, Biblical Chronology, Early Modern Science.

1. INTRODUCTION

The most important and lasting contribution that Nicolaus Steno (1638-
1686) left to modern science is the 78-page book titled The Prodromus to a 



60 Stefano Dominici

Dissertation on a Solid Naturally Contained Within a 
Solid (the Prodromus in short).1 The dissertation that the 
title alluded to never followed, and the Prodromus was 
the last published scientific essay of the intense and brief 
career of a young researcher bound to influence his gen-
eration of natural philosophers.2 Most of his precedent-
setting works were centered on anatomical research and 
the study of the animal body, but the Prodromus dealt 
with crystals, fossils and rocks. Why turning to a dif-
ferent subject? And why Steno accepted the parallelism 
between the natural history revealed in the rock record 
and the biblical narrative? Since his scientific endeavour 
ended in coincidence with his conversion to Catholi-
cism and the start of a vocation in theology, modern 
understanding has to deal with history of science and 
history of religion at the same time. Consequently the 
aim behind the Prodromus remains obscure unless read-
ers are familiar with both contexts. According to biog-
raphers who emphasized Steno’s role in the history of 
science, such as the late Gustav Scherz (1895-1971), the 
standard story is that Steno turned to the study of fos-
sils in 1666 when he realized, while casually studying 
the anatomy of a shark’s head, that fossils called glosso-
petrae (meaning “tongue stones”) were actually shark’s 
teeth and not, as generally supposed, sports of nature. 
A second widely-accepted narrative suggests that deny-
ing biblical chronology in the face of hard empirical 
evidence was “a losing game,”3 so that Steno “contin-
ued to hesitate about the implications of his finding”4 
and in the final chapter of the Prodromus “took care to 
reassure readers that his science did not contradict the 
Bible.”5 This emphasis implies that during those years 
some empirical evidence, or science in the modern 
sense, could undermine the credibility of biblical chro-
nology. Historians of religion know very well, however, 
that it was not natural philosophy, but textual criticism 
itself, which at that time called into question Scripture. 
Furthermore, criticism stemmed from disputatious free-

1 N. Stensen, De Solido Intra Solidum Naturaliter Contento Dissertationis 
Prodromus, Florence, Stella, 1669 (Prodromus in following notes). Eng-
lish translation, pp. 621-660, in T. Kardel, P. Maquet, Nicolaus Steno, 
Biography and Original Papers of a 17th Century Scientist, 1st edition, 
Heidelberg, Springer, 2013 (K&M in following notes).
2 A treatise on precious stones, written after the Prodromus, was never 
published, indicating that Steno left the scientific community by 1669: 
F. Sobiech, in The Revolution in Geology from the Renaissance to the 
Enlightenment (Ed.: G. D. Rosenberg), Geol. Soc. Am. Mem., 2009, 203, 
179-186.
3 A. Cutler, The seashell on the mountaintop. Dutton, New York, 2003, 
pp. 5-16, 115-122, 191-192.
4 P. Findlen, Possessing Nature: museums, collecting and scientific culture 
in early modern Italy University of California Press, Berkeley, 1994, p. 
237.
5 R. Rappaport, When geologists were historians, Cornell University 
Press, Ithaca and London, 1997, p. 201.

thinkers, such as the French Isaac La Peyrère (1596-1676) 
and Richard Simon (1638-1712), Isaac Vossius (1616-
1689) and Baruch Spinoza (1632-1677) in the Dutch 
Republic, and Francis Lodwick (1616-1694) in England, 
people who had no public followers of their caliber until 
the second half of the eighteenth century.6 Indeed, bibli-
cal chronology was understood to be a science with its 
worthy followers, and seventeenth-century natural phi-
losophers did not doubt that the Book of Genesis was a 
reliable historical account of the distant past. This need-
ed interpretation, the reason why a science of biblical 
chronology was necessary.7 This means that the parallel-
ism drawn by Steno in the last chapter of the Prodromus 
between an empirical reconstruction of historical events 
and the biblical account, from Creation to repopulation 
of the Earth after the Deluge, was not motived by fear of 
the authorities of the Church to which he had recently 
converted, as instead suggested by some.8 Steno, like any 
other natural philosopher of his time, took the Bible as 
“obviously and predominantly historical,” an account to 
be carefully interpreted using all available translations.9 
The evidence presented in the present paper reinforces 
the opinion that Steno sincerely wanted to prove that he 
had found a limited, but relevant and additional means 
to reconstruct history. Steno’s latest scientific produc-
tion is underlain by a search for true religion and a way 
to reconcile natural philosophy and biblical revelation, 
in years when unorthodox thinking triggered debate in 
northern Europe.10 It is suggested that Steno actually 
had planned field work before moving from Paris to Tus-
cany.

The standard point of view is therefore disputed and 
it is hypothesised that the young Dane knew that in Italy 
he could find evidence for a reconstruction of primordial 
history based on an unprecedented way to study crys-
tals, fossils and rocks. Since his student years, Steno’s 
multifaceted general research plan to uncover the mys-
teries of God’s Creation included aspects of his ongoing 

6 R. Rappaport in ref. 5, p. 76. Criticism towards historicity of the bibli-
cal narrative was discussed only privately, and in small circles: see an 
eloquent example in W. Poole, Scripture and Scolarship in Early Modern 
England (Eds. A. Hessayon, N. Keene), Ashgate, Aldershot, Hampshire, 
2006, pp. 41-56
7 M. J. S. Rudwick, Earth’s deep history. Chicago University Press, Chi-
cago, 2014, pp. 9-30.
8 A. Cutler in ref. 3,  pp. 5-16, 192.
9 Quote and emphasis from R. Rappaport in ref. 5, p. 72. On the role of 
the different translations of the Bible see E. Jorink, “ “Horrible and blas-
phemous”: Isaac La Peyrère, Isaac Vossius and the emergence of radical 
biblical criticism in the Dutch Republic,” in Nature and Scripture in the 
Abrahamic religions: up to 1700 (Eds. J. M. van der Meer, S. Mandel-
brote), Brill, Leiden, 2016, pp. 429-450.
10 S. Miniati, Nicholas Steno’s challenge for truth. Reconciling science and 
faith, Milan, Franco Angeli, 2009, 336 p. 



61A Man with a Master Plan: Steno’s Observations on Earth’s History

studies of anatomy, and other studies aimed at proving 
the historicity of the biblical account by geometrical 
means. His contemporaries understood the Prodromus 
as such, looking forward to seeing the full dissertation 
published.

It is questioned whether Steno’s interest in the origin 
of fossils stemmed from a serendipitous discovery that 
glossopetrae were shark’s teeth (a finding already pub-
licly demonstrated in 1616 by Fabio Colonna).11 Instead 
of moving top-down from philosophical, metaphysical 
and theological questions that mattered to Steno and his 
peers, this study reconsiders the timing with which he 
collected geological data in Tuscany, what textual sourc-
es on local paleontological sites he most certainly drew 
from, and his relationships with a network of sources. 
The amount of data he swiftly collected and the conclu-
sions he drew in the very first months after his arrival 
in Florence imply that he had planned to do geological 
research, a plan that ultimately related to chronology of 
biblical events and had of course something to do with 
debates on the intepretation of Scripture occurring in 
cultural circles that he had frequented before 1666. 
Those circles embodied the spirit of the ‘new philoso-
phy’, as termed by John Donne in 1611,12 and at least in 
part coincided with ‘the Republic of Letters’, a trans-
national community that cultivated science based on 
observation, experiments and mathematics, not on scho-
lastic authority.

His work in Tuscany, started at the age of 28, 
came at the climax of a series of readings and experi-
ences traced back to 1659, when he was 21 years-old. 
These had made him receptive to evidence concerning 
the nature of fossils and sedimentary rocks and will 
be reviewed as such. Learned men at the Medici court 
were connected with European intellectual circles and 
would have offered Steno plenty of knowledge on geo-
logical matters. The Italian tradition dealing with Re 
Metallica, “metallic things”, or geological data in the 
modern sense, with studies practiced by Italian Renais-
sance and early modern writers, such as Andrea Cesal-

11 F. Columnus, De Glossopetris Dissertatio. In Fabii Columnae Lyn-
cei Purpura, Rome, 1616, pp. 31-39. See M. J. S. Rudwick, The mean-
ing of fossils. Episodes in the history of paleontology, Chicago, Universi-
ty of Chicago Press, 2nd edition, 1976 [1972], pp. 42-44; A. Ottaviani, 
“La natura senza inventario: aspetti della ricerca naturalistica del linceo 
Fabio Colonna”, Physis, 1997, 34, pp. 31-70.
12 “And new philosophy calls all in doubt,/The element of fire is quite 
put out,/The sun is lost, and th’ earth, and no man’s wit/Can well direct 
him where to look for it:” J. Donne, conclusion from An Anatomy of the 
World, cited in D. Wootton, The invention of science: a new history of the 
scientific revolution, New York, Harper Perennial, 2015. Donne writes 
about a ‘new philosophy’ a year after the publication of Galileo Galilei’s 
Sidereus Nuncius, and is thus identified by Wotton as the first account-
able testimony to the birth of modern science.

pino (1524-1603), Michele Mercati (1541-1593), Ferrante 
Imperato (1550-1631) and Fabio Colonna (1567-1640) 
was famed enough to attract Steno to visit cabinets of 
natural history and rock outcrops from which geologi-
cal specimens came. The geological data he referred to 
have remained somewhat obscure, because none of the 
essays he published in Italy, with few exceptions, con-
tain clear information on location and description of 
specific places he visited and specimens he studied. This 
situation has influenced the perception of the Prodro-
mus as an abstract work that assembled an “odd array 
of material,”13 an opinion that the present paper will 
attempt to dispel.

2. A MAN WITH A PLAN

Steno’s philosophical and religious background 
must be recalled in order to understand the reason 
he searched for confirmation of Scripture in Nature. 
Empiricism underlay bot h his natura l philosophy 
and his theolog y14 and transcended what is recog-
nized today as a separation of physics from metaphys-
ics. Within the physical world, Steno dealt jointly with 
‘geological ’, chemical and anatomical obser vations. 
This he did in the light of the Scripture since at least 
1659, when he recorded in his journal, entitled “Chaos”, 
lessons which he derived from the writing of others.15 
This collection of extracts, an aid for the memory when 
he was a student and a sort of commonplace book,16 is 
Steno’s oldest known manuscript. It starts with words 
and concepts directly referred to the Christian Faith 
and the writings of Moses, the purported author of the 
Book of Genesis:

In the name of Jesus
CHAOS
Not out of Aristotle’s [elements]

13 R. Rappaport in ref. 5, pp. 99-101; but see M. J. S. Rudwick, The 
meaning of fossils. Episodes in the history of paleontology, Chicago, Uni-
versity of Chicago Press, 2nd edition, 1976 [1972], pp. 58-60; D. Garber, 
Steno and the Philosophers (Eds.: R. Andrault, M. Lærke), Brill, Leiden, 
2018, (A&L in following notes), pp. 201-232.
14 F. Sobiech, Ethos, bioethics, and sexual ethics in work and reception of 
the anatomist Niels Stensen (1638-1686), Springer, 2016, pp. 30-35.
15 A. Ziggelaar in N. Stensen, Acta Hist. Sci. Nat. Med. (Ed.: A. Zigge-
laar), 1997 [1659] (Chaos in following notes), 44, 453 pp.; G. D. Rosen-
berg, Geol., 2006, 34, pp. 793-796; S. Olden-Jørgensen, in ref. 2 (Rosen-
berg), pp. 149-157.
16 The practice of writing commonplace books, a form of text collec-
tions, emerged particularly during the late Renaissance and remained 
in use among literate people during the early modern age: E. Havens, 
Commonplace books: a history of manuscripts and printed books from 
antiquity to the twentieth century. University Press of New England, 
2002, 99 pp. 



62 Stefano Dominici

That man is composed of the four elements is against Holy 
Scripture, where Moses only mentions water and earth. For 
Aristotle’s air nowhere appears and fire is an accident. […] 
bodies are only resolved into water and earth.17

The first two lines can be regarded as a synthesis 
of the first part of the Creation seen form a Christian 
perspective: “in the beginning was the Word […] and 
the Word was God” (meaning Jesus), says the Prologue 
according to the evangelist John. In this sense, ‘In the 
name of Jesus’ right before ‘CHAOS’ becomes God’s 
word commanding order to raise from non-order. This 
last concept is confirmed in a later remark in Steno’s 
Elementorum Myologiae Specimen of 1667: “in Holy 
Scripture it is said that the world has come forth from 
‘unseen’ matter as from chaos.”18 The other part of the 
opening regards the third day of the biblical Creation, 
when God separated dry land from water. Steno quoted 
the passage from the surgeon Cornelius Schylander’s 
Practica chirurgiae brevis et facilis (1575),19 where the 
authority of Aristotle on the number of elements is sub-
mitted to the authority of the Bible: the basic elements 
all bodies are made of are water and earth (air and fire 
being secondary). Furthermore, taking the point of view 
of a student writing not for publication, Steno’s private 
collection of excerpts seems also to start with an auspice 
that his knowledge be ordered, from the chaotic form 
of the commonplace book into that of a mature anato-
mist.20 Several times Steno, while excerpting the books 
he was reading, fell into despair and doubted his abil-
ity to bring order to the many subjects he approached.21 
He subtly declared an attempt to reach a unitary com-
prehension of nature and in the same page he confirmed 
that ‘the profane is not to be excluded from the sacred’ 
(a quote taken from Jeremias Drexel’s Ioseph Aegypti 
prorex descriptus of 1641).22

Most of the above, written in 1659, are about medi-
cal matters, but water, earth and Scripture are for the 
first time related with fossils in some revealing quotes 
taken from Pierre Borel’s Historiarum et observationum 

17 N. Stensen, Chaos, in ref. 15, p. 21.
18 N. Stensen, Elementorum Myologiae Specimen, seu Musculi Descriptio 
Geometrica, in ref. 1 (K&M), p. 435; J. Smith, in ref. 13 (A&L), pp. 177-
200.
19 A. Ziggelaar, in ref. 15, p. 103.
20 Francis Bacon praised the activity of text collecting in his The 
advancement of learning: “there scarcely can be a thing more use-
ful, even to ancient, and popular sciences, than a solid, and good aid 
to memory; that is, a substantial and learned digest of common places. 
[…] I hold that the diligence and pains in collecting commonplaces, is 
of great use and certainty in studying”: quoted in E. Havens, The Yale 
University Library Gazette, 76, 2002, pp. 136-153.
21 F. Sobiech, in ref. 14, pp.  59-61.
22 N. Stensen, Chaos, in ref. 15, p. 22; Smith, in ref. 2, p. 197.

Medico-Physicarum (1656). In a passage Steno focused 
on analogies between the human body and the Earth 
that allowed him to realize that marine fossils were evi-
dence of an “ancient deluge”.

Singular stones of the bladder, shells turned into stones. 
Therefore stones in places that lie very far from the sea, it 
is certain that seas change their beds. In the right kidney a 
grey stone was observed, in the left kidney clay. […]
Snails, shells, oysters, fish etc. found petrified on places far 
remote from the sea. Either they have remained there after 
an ancient deluge or because the bed of the seas has slowly 
changed. On the change of the surface of the Earth I plan a 
book.23

The last sentence, although taken from Borel, may 
well allude also to Steno’s program, at least denot-
ing what he considered worthy of serious consideration 
when he was 21. The original  Borel’s text reports that: 

Near the town of Montpellier I found large petrified oys-
ters, mussels and even fossil fishes […] all these things show 
that in ancient times the flood for long covered this place 
(as discovered also elsewhere, very far from the sea), that is 
to say that the sea has changed position, (which I will prove 
in my book ‘On the changed position of the globe’, and at 
other places I saw dragon’s teeth), so the sea receded from 
innumerable places.24 

The importance of quotes taken from this contem-
porary French cartesian philosopher is underlined by 
side notes made by Steno in the 1659 manuscript.25 The 
above passage also indicates the region around Montpel-
lier as one where marine fossils occur, suggesting why 
Steno sojourned in that town of southern France in win-
ter 1665-1666, before continuing his trip to Tuscany.

As a young student, Steno approved the method of 
inquiry laid out by René Descartes in the Discourse de 
le méthode (1637) and Les Principes de la philosophie 
(1644), without sharing the cartesian preference to sepa-
rate natural philosophy from theology.26 In the words 
of historian of science Justin E.H. Smith, young Steno 
appears “speculative, somewhat mystically inclined, 

23 N. Stensen, Chaos, in ref. 15, pp. 46, 58-59. The original Borel’s text 
relates the presence of marine fossils with the biblical flood, with writ-
ing a book on the argument.
24 P. Borel, Historiarum et observationum Medico-Physicarum, Billaine, 
Paris, 1656, p. 261. The italics are in the original text and refer to the 
title of the book that Borel had planned to write.
25 A. Ziggelaar, in ref. 2 (Rosenberg), pp. 135-142. J. Bek-Thomson, ref. 
2 (Rosenberg), p. 289. 
26 E. Jorink, Reading the book of nature in the Dutch Golden Age, 1575–
1715, Brill, Leiden, 2010, p. 16. See also Olden-Jørgensen in ref. 2 
(Rosenberg), pp. 149-157. On the role of Borch in directing Steno’s edu-
cation, see A. Ziggelaar, in ref. 2 (Rosenberg), pp. 135-142.



63A Man with a Master Plan: Steno’s Observations on Earth’s History

and at the same time keen on absorbing the latest les-
sons from empirical natural philosophy, including those 
of Bacon, Descartes, and others, even when these come 
from thinkers who do not share the same mystical and 
theological concerns.”27 When in 1661 he went to study 
medicine in the Low Countries, he connected with the 
circle of Dutch savants and curieux, first in the hotbed 
of radical thinkers that was Amsterdam, then in near-
by Leiden. There he had relations “far from marginal” 
with the unorthodox philosopher Baruch Spinoza28 
and the innovative physician Johannes Swammerdam.29 
Swammerdam and Steno were fellow students and close 
friends in Leiden from 1661-1663 and then in Paris in 
1664, the two sharing a motivation to search for a bridge 
between natural philosophy and true religion. Swam-
merdam maintained that skilful dissections of animals, 
even insects, disclosed to the anatomist the immense 
wisdom that God had instilled in the minutest parts 
of creation. The two came to believe that ‘studying the 
intricate fabric of anatomical structures was a tribute to 
God, the omniscient architect’.30 They lived in a critical 
place at the critical time for the future of religion when, 
following the interventions of Descartes and Spinoza, 
‘the relation between belief and natural science became 
problematic’.31 The philosophy underlying Steno’s and 
Swammerdam’s research consciously moved away from 
the Deus sive natura principle of Spinoza, a motto that 
denoted the identity between the infinite substance of 
God and the finiteness of Nature. The two chose instead 
a religion grounded on ‘the argument from design’, the 
idea that God is not identical to nature, but is the great 
Architect, whose brilliance can be deduced from the 
‘great fabric of the world’.32

Historiographers still discuss if, in his early twen-
ties, Steno was a genuine Lutheran33 or a deist, however 
“sui generis”,34 yet opinions converge in depicting those 
years as a period during which he gradually lost faith 
in cartesian dogmatism and a mechanistic perspec-
tive, instead becoming more meditative and inquisitive 
in religious matters. In autumn 1664 he joined Swam-
merdam in Paris, where, for nearly a year, both were 

27 J. E. H. Smith, in ref. 13 (A&L), pp. 177-200.
28 Quote from P. Totaro, “Ho certi amici in Ollandi”, Analecta Romana 
Instituti Danici, 2002, suppl. 31, pp. 27–38. On the relation between 
Steno and Spinoza, see also G. Scherz, in ref. 1 (K&M), pp. 91-92, and 
particularly S. Miniati, Scienza, filosofia e religione nell’opera di Niels Ste-
ensen (Eds. M. A. Vitoria, F. J. Insa Gómez), Pagnini, Firenze, 2020, pp.
29 E. Jorink, in ref. 13 (A&L), p. 16.
30 E. Jorink, quoted in ref. 13 (A&L), p. 29.
31 E. Jorink, quoted in ref. 13 (A&L), p. 16.
32 E. Jorink, quoted in ref. 13 (A&L), p. 18.
33 S. Miniati, ref. 10.
34 S. Olden-Jørgensen, in ref. 2 (Rosenberg), pp. 149-157; F. Sobiech, ref. 
14.

hosted by Melchisédec Thévenot (1620-1692). Thévenot 
had been a diplomat in Italy during the 1650s, and was 
an experimentalist in close contact with the Accademia 
del Cimento in Florence, himself hosting a sort of acad-
emy in his house. There Steno met with Pierre Borel and 
admired his skills, as he recalled two years later:

In Paris, in the Academy at the house of my great friend 
Thévenot, I have seen Borel, greatly skilled in chemistry, 
pour together two quite clear liquids which immediately 
became so solid that not even a drop left the glass container 
when it was inverted.35

Thévenot was also a collector of travel accounts from 
long-distance voyagers and the owner of a cabinet of 
curiosities.36 Among Thévenot’s other connections was 
Athanasius Kircher, founder in 1651 of ‘Museum Kirche-
rianum’ in Rome. In the early 1660s Kircher’s popular-
ity was immense, based on his encyclopaedic interests, 
vast experience, and even vaster imagination regarding 
late Renaissance visions in natural matters that often 
conflicted with the new philosophy. Savants throughout 
Europe, including Prince Leopold of Medici37 in Flor-
ence, had been awaiting the publication of his Mundus 
subterraneus in 1664,38 preceded in 1641 by Magnes sive 
de arte magnetica, extensively quoted in Steno’s Chaos.

One of Kircher’s disciples on sinology at the Roman 
College was the Jesuit missionary Martino Martini, 
author in 1658 of ‘History of China’,39 a book that pro-

35 N. Stensen, Canis Carchariae Dissectum Caput, Florence, Stella, 1667 
(Canis Carchariae in following notes). English translation in ref. 1 
(K&M), p. 591.
36 N. Dew, in Bringing the World to Early Modern Europe: Travel 
Accounts and Their Audience (Ed.: Mancall), Brill, Leiden, 2007, p. 49. 
The correspondence between Thévenot and future members of the 
Cimento Academy dated back to 1643, continued through the years and 
included letters to Prince Leopold of Medici, in Florence, on experi-
mental matters (1660-1666): ref. 38 (MG); W. E. K. Middleton, The 
Experimenters: a study of the Accademia del Cimento, John Hopkins 
Press, Baltimore, 1971, 415 pp.
37 Prince Leopold of Medici (1617-1675) promoted the publication of 
Galileo Galilei works (1655-1666) and the activities of the Accademia 
del Cimento (1657-1667): Knowles Middleton, ref. 36; A. Mirto, Dizion-
ario Biografico degli Italiani, 2009, 73, pp. 106-12. As an erudite collec-
tor of art and antiquities, in 1662-1668 he had established a productive 
European network: S. Dall’Aglio, J. Hist. Collect. 12/12/2019, pp. 1-12.
38 W. C. Parcell, in ref. 2 (Rosenberg), p. 64-66; letter by A. Kircher (15 
august 1965) to Prince Leopold, in digital archive, Museo Galileo (MG 
in following notes), Gal. 277, f. 215r: https://www.museogalileo.it/it/
biblioteca-e-istituto-di-ricerca/biblioteca-e-archivi/archivio-storico.html 
(accessed on 24 May 2020).
39 ‘Historia’ of the title retains its traditional significance of ‘collection of 
facts’, not its reductive modern use as ‘chronology of events’. This is evi-
dent from Martini’s address to the reader, ‘Extrema Asia sive Sinarum 
Imperii compendio & annorum ordine comprehensam Historiam’: M. 
Martini, Sinicae Historiae, Blaeu, Amsterdam, 1659, p. 6. For the use of 
‘Historia’ in Steno and his contemporaries, see J. Bek-Thomsen, in ref. 



64 Stefano Dominici

posed a chronology different from the biblical.40 It is rea-
sonable to suppose that Steno discussed Earth’s history 
at Thévenot’s circle in 1664-1665, in the wake of debates 
in Amsterdam circles of freethinkers, where the idea that 
human history is older than history told in the Old Tes-
tament had found sustainers41 and the universality of 
the noachian flood was questioned.42 A new type of ana-
tomical observation, this time on a grand scale, so as to 
see the body of the Earth cut open, would have pushed 
him to move south where he knew he could observe fos-
sils on the field.43 Thévenot formed a bridge with the lib-
eral court of Ferdinand II, Grand Duke of Tuscany, and 
his brother, Prince Leopold. At the Medici court another 
international circle had gathered, including the French 
oriental philologist Barthélemy d’Herbelot (1625-1695). 
By moving to Florence Steno could hope to earn a wage 
to pursue his research, whether on muscles or on fossils 
and their context.44 The Florentine Carlo Dati (1619-1696), 
one of the members of the Accademia del Cimento and 
a correspondent with learned men from Paris,45 was also 
a correspondent of Thévenot’s. Steno had probably heard 
in advance about the paleontological heritage of Tuscany, 
well known to Carlo Dati as it will be shown. From Tus-
cany he could move further south, until eventually reach-
ing Sicily and Malta and there collect other fossils.

First in the Dutch Republic, then in Paris, Steno was 
thus in the middle of a fierce polemic on which he could 
hardly remain neutral, judging from his inquisitivity on 
religious matters. 

2 (Rosenberg), pp. 296-297; N. Morello, Niccolò Stenone e la scienza in 
Toscana alla fine del ‘600 (Eds.: L. Negri, N. Morello, P. Galluzzi), Lau-
renziana, Firenze, 1986, pp. 67-89.
40 Martino Martini (1614-1661) dominated European knowledge of Chi-
na in the period 1654-87: N. Dew, Orientalism in Louis XIV’s France, 
Oxford University Press, Oxford, 2009, 302 p.; E. Jorink, D. Miert, Isaac 
Vossius (1618-1689) between science and scholarship, Brill, Leiden, 2012, 
352 p.; see also R. Rappaport, ref. 5.
41 Martini’s book influenced the reception of the preadamite theory by 
Isaac La Peyrère (1596-1676), particularly in the Dutch Republic start-
ing from the late 1650s: R. H. Popkin, Isaac La Peyrère (1596-1676): 
his life, work, and influence, Brill, Leiden, 1987, pp. 85-87; J. L. Mor-
row, Three skeptics and the Bible: La Peyrère, Hobbes, Spinoza, and their 
Reception, Eugene, Pickwick, 2016, pp. 83-84; A. Grafton, “Isaac Vossi-
us, Chronologer”, in ref. 40 (E. Jorink, D. Miert), pp. 43-84.
42 A. Ottaviani, Giorn. Crit. Filosof. It., 2017, 13, 272-301.
43 J. Bek-Thomsen, in ref. 2 (Rosenberg).
44 N. Dew, ref. 40, pp. 62-76. ‘For many years, a prominent position 
inside the Medici Court meant an attractive lifestyle and high wages’: 
L. Boschiero, Experiment and natural philosophy in seventeenth-century 
Tuscany. The history of the Accademia del Cimento, Springer, Dordrecht, 
2007, p. 20.
45 Carlo Roberto Dati, humanist, disciple of Galileo and experimental-
ist, in close contact with Jean-Baptiste Colbert, Minister of the Finances 
under Louis XIV, was consulted in 1666 for the birth of the Académie 
de Sciences. See N. Dew, ref. 40, p. 53, and W. E. K. Middleton, ref. 36.

3. THE NATURE OF TUSCANY

Steno arrived in Tuscany in April 1666. Ferdinand 
II and Prince Leopold recognized him as an outstanding 
natural philospher, an anatomist whose public dissection 
of a human brain performed in Paris in October, 166546 
proved Descartes wrong about the manner in which 
this organ functions.47 By December of the same year, 
Steno had completed the essay Canis Carchariae Dis-
sectum Caput which ended with a “digression on bod-
ies resembling parts of animals that are dug from the 
earth”, a writing where ‘tongue stones” were interpreted 
as sharks’ teeth.48 This essay was subsequently published 
in April 1667 as an appendix to his treatise on myolo-
gy.49 The interpretation of the dissection as the start-
ing point of a research on fossils is probably based on 
Steno’s brief account of his scientific career, written in 
the opening pages of the Prodromus (“To take me away 
from a detailed account of the muscles, a shark of pro-
digious size was thrown up by your seas”),50 a rhetorical 
artifice to emphasize that in his life he had been accus-
tomed to submit to someone else’s will. Instead, he could 
hardly collect all evidences contained in the ‘digression’ 
between October51 and December, so he had carried out 
the many observations on fossils and the sedimentary 
strata in which they were found before the dissection. As 
for the reason to carry out any field activity, Canis Car-
chariae already shows that his interest for marine fossils 
was related to two events narrated in the Scripture, two 
cornerstones of Earth’s history presented in the Prodro-
mus. The first event was the separation of solid matter 
from fluid, on the third day of Creation (“And God said, 
‘Let the waters under the sky be gathered together into 
one place, and let the dry land appear’”: Gen 1, 9), an 
interest foreshadowed by the opening quote of the Chaos 
manuscript (see above note 17). The second event was 
the Universal Deluge (“The flood continued forty days 
on the earth; and the waters increased, […] and it rose 
high above the earth”: Gen 7, 17), referred to in Borel’s 
quote transcribed in 1659 (see above notes 23-24). Both 
events relate to a universal fluid covering all or most of 
the globe.

Canis Carchariae reports that different types of fos-
sils were contained in two types of strata, one hardened 
the other soft, separated by surfaces that deviated from 

46 N. Stensen, Discours sur l’anatomie du cerveau, Paris, Ninville, 1669. 
English translation in K&M, pp. 507-527; R. Andrault in ref. 13 (A&L), 
pp. 87-112.
47 A. Cutler in ref. 3, p. 53.
48 N. Stensen, Canis Carchariae, in ref. 1 (K&M), pp. 571-595.
49 N. Stensen, Myologiae Specimen, in ref. 1 (K&M), pp. 545-570.
50 N. Stensen, Canis Carchariae, in ref. 1 (K&M), pp. 623-624.
51 A. Cutler in ref. 3, p. 53.



65A Man with a Master Plan: Steno’s Observations on Earth’s History

horizontality (a geometric character that implies tilting 
of strata after their deposition and that would become a 
central argument of the Prodromus):

The soil from which bodies resembling parts of aquatic ani-
mals are dug is in certain places rather hard, like tufa and 
other kinds of stone; in other places it is rather soft like clay 
or sand […]. In various places, I have seen that the said 
soil is composed of layers superimposed on each other at 
an angle to the horizon. […] In those soils that I have been 
able to observe up to now, bodies of different kinds have 
been concealed in the same soil, sometimes in the harder, 
and sometimes the softer sort. I have observed that the 
number of these bodies in clay is quite large in the surface 
but quite small in the soil itself .52
Very many oyster shells are found in some regions, 
deformed and hardened into one lump; sometimes also, 
broken scallops and mussels are dug up; some people have 
seen, in the same place, many tongue stones clinging as it 
were to the same matrix.53

Based on the comparison of ‘tongue stones’ with 
the teeth of the large shark he had dissected, he hypoth-
esised in the essay that they did not grow in the earth, 
an opinion still held by many.54 Steno had surely seen 
‘tongue stones’ in Copenhagen in the museum of Ole 
Worm (1588-1654),55 and learned about them through 
his teacher Thomas Bartholin (1616-1680), who had writ-
ten a book on glossopetrae after travelling to Malta in 
1644.56 But he had never seen them in earlier travels:

I do not yet have the knowledge of this matter [the tongue 
stones] to pass judgment on it here; and though my travels 
have taken me through various places of this kind, never-
theless, I do not dare to guarantee that what I shall observe 
in the rest of my journey will be similar to what I have 
observed up to now. Chiefly, since I have not yet seen what 
my very famous teacher Bartholin observed in his journey 
to Malta.57

‘Several places of this kind’ refers to localities of 
outcrops where assemblages of marine animal fossils 
are embedded in compact or hardened rock. Follow-
ing Borel’s indication, he had possibly seen strata with 

52 N. Stensen, Canis Carchariae, in ref. 1 (K&M),  p. 585.
53 N. Stensen, Canis Carchariae, in ref. 1 (K&M),  p. 586.
54 N. Morello, ref. 39.
55 For the Museum Wurmianum in Copenhagen and its role for Steno’s 
upbringing, see Rosenberg, ref. 15 and appendix; for the significance 
of private museum collections for seventeenth century natural philoso-
phers see Rappaport, ref. 5, pp. 53-55.
56 Bartholin’s essay on glossopetrae is now lost. Scherz, in ref. 1 (K&M), 
p. 38; A. Ziggelaar in ref. 15, pp. 466-469; I. H. Porter, Med. hist., 7, 
1963, pp. 99-125; A. Ottaviani, Schede Umanistiche, Riv. sem. Arch. Um. 
Rin. Bol., 2004, 2, pp. 89-110.
57 N. Stensen, Canis Carchariae, in ref. 1 (K&M), p. 585.

marine shells around Montpellier, where he had met 
with other savants interested in the study of fossils, such 
as John Ray (1627-1705) and Martin Lister (1638-1717).58 
Above all, he must have been informed that Tuscany was 
particularly suited to carry out that type of fieldwork. 
Although ‘tongue stones’ were difficult to find, fossils 
they were usually associated with were a useful substi-
tute (see comment ‘some people have seen, in the same 
place [of oysters, scallops and mussels], many tongue 
stones’ above).59 The most important influence was an 
unpublished ‘field guide’ by the Tuscan Michele Mer-
cati, a manuscript handed to him in Florence.60 In the 
preceding century, Mercati had systematically arranged 
the Pope’s collection of minerals, stones and fossils in 19 
large and expensive cabinets to form the Vatican muse-
um called Metallotheca. The manuscript was owned by 
Carlo Dati, who had lent Steno two of the engravings 
made for the Metallotheca which the Dane used to illus-
trate the Canis Carchariae essay,61 as well as the manu-
script itself. This told about ‘instructions’ that interested 
Steno, as he himself revealed:

Mercati’s manuscript [contains] much that is well worth 
knowing and a wealth of varied instruction about soils, 
salts, oily fluids, stones, bodies of idiomorphic shapes, and 
so on; this manuscript would have remained buried in eter-
nal darkness, had not the very learned Dati’s skill brought 
it out of the underworld and provided an opportunity for it 
to be exposed to the light of day.62

Mercati revealed that at his hometown of San Mini-
ato (locality 3 in Fig. 1), a place famous for marine 
shell beds as recorded also by Leonardo da Vinci (1453-
1519),63 large tongue stones were found with oysters (Fig. 
2). Mercati had subdivided tongue stones on the basis 
of size and shape and pictured them in three beautiful 

58 G. Scherz, in ref. 1 (K&M), pp. 137-140.
59 The association of fossil shark teeth with seashells was also described 
in Fabio Colonna’s De Glossopetris Dissertatio: ref. 10. M. Rudwick, ref. 
13, pp. 42-44; N. Morello, ref. 39, p. 71.
60 Michele Mercati (1541-1593) and his teacher Andrea Cesalpino 
(1519-1603) were leading figures in late Renaissance study of res metal-
lica. Cesalpino ordered the Medicean collection of natural history and 
completed Mercati’s systematic work in De Metallicis (1596). See U. 
Viviani, Vita ed opere di Andrea Cesalpino, Viviani, Arezzo, 1917, pp. 
186-187, 218-219; B. Accordi, Geologica Romana, 1980, 19, pp. 1-50; P. 
Findlen, in ref. 4, pp. 61, 233-235; for the Medicean gallery of natural 
history in Pisa, certainly visited by Steno already during the first part of 
his stay, see L. Tongiorgi Tomasi, Giardino dei Semplici. L’Orto Botani-
co di Pisa dal XVI al XX secolo (Eds.: F. Garbi, L. Tongiorgi Tomasi, A. 
Tosi), Pacini, Ospedaletto, 1986, pp. 161-170.
61 J. Bek-Thomsen, in ref. 2 (A&L), pp. 233-258.
62 N. Stensen, Canis Carchariae, in ref. 1 (K&M), p. 572
63 E. Cioppi, S. Dominici, in Water as microscope of nature. Leonardo da 
Vinci’s Leicester Codex (Ed.: P. Galluzzi), Firenze, Giunti, 2018, pp. 171-
183.



66 Stefano Dominici

drawings that were engraved, together with all other 
plates, by the German artist Anton Eisenhoit (1553-
1603). One type belonged to large sharks which we now 
know as the great white (Carcharodon carcharias), as the 
one dissected by Steno. In the words of Mercati:

I received very beautiful [large tongue stones] from my 
father, fortuitously found in a field near San Miniato. […] 
Ostracites [fossil oysters] are found in fields near the towns 
of Siena and San Miniato.64

Evidence is thus consistent with an hypothesis that 
Steno studied fossiliferous strata of Tuscany early in 
1666. Consequently, when he had an opportunity to dis-

64 M. Mercati, Michaelis Mercati Samminiatensis Metallotheca: opus pos-
thumum, auctoritate & munificentia Clementis undecimi pontificis maxi-
mi e tenebris in lucem eductum: opera autem & studio Joannis Mariæ 
Lancisii archiatri pontificii illustratum, Roma, Salvioni, 1717 [1593], p. 
48.

sect the head of a shark, his mind was already set. This 
explains the rapidity with which he published, hasten-
ing to secure a priority on the subject. At San Mini-
ato he would also observe sandy and clayey strata, some 
cemented, most simply compacted, crop out in the steep 
flanks of the hill where the town is built. These strata are 
slightly inclined towards NNE (Fig. 3), so this is one of 
those places, in which he would have seen ‘that the said 
soil is composed of layers superimposed on each other 
at an angle to the horizon’ (see note 52 above), meaning 
they had been tilted after deposition.

The study of sedimentary strata allowed Steno 
to prove that water twice covered the Tuscan relief, 
acknowledging that observation of nature and words in 
Scripture work in pair:

Nor can there be strong opposition to the belief that the 
said soil was once covered with water.  […] [If] we assume 
that this piece of ground always had the same situation, 

Figure 1. Schematic map of Tuscany showing localities mentioned in the present paper, in relationship with Steno’s Prodromus description 
of strata on which he based his history of the Earth. These localities are: 1) Monte Ceceri, 2) Gonfolina, 3) San Miniato, 4) Volterra, 5) Chi-
ana Valley. Original graphic by the author.



67A Man with a Master Plan: Steno’s Observations on Earth’s History

[…] we learn from Holy Scripture that all things, both at 
the beginning of creation, and at the time of the Flood, 
were covered with water.65 Tertullian writes elegantly about 
this: “A change occurred in the whole world when it was 
covered with all the waters; even now, sea shells of mussel 
and whelk range over the mountains seeking to prove to 
Plato that the very peaks have been under water.66

Steno’s digression in Canis Carchariae revolves 
around the demonstration of the marine origin of fossils 
(he explains this through “conjectures” numbered 1-4, 6) 

65 N. Stensen, Canis Carchariae, in ref. 1 (K&M), p. 587. Morello, ref. 
39, p. 77.
66 N. Stensen, Canis Carchariae, in ref. 1 (K&M), p. 587.

and the precipitation of solids from liquids (conjectures 
4-5, indicating ‘the ways in which solid bodies hidden 
in water may be secreted’). Judging from the subsequent 
development of these two topics in the Prodromus, this 
means that in 1666 not only had Steno already studied 
fossiliferous mudstones and sandstones at the top of 
the Tuscan sedimentary succession (his evidence of ‘the 
Flood’), but also older unfossiliferous strata which he 
thought formed at ‘the beginning of creation’ (see above, 
and note 65), when God separated earth from a primor-
dial fluid.

4. THE ITALIAN NETWORK

In 1667 Steno shared his thoughts on fossils with 
other learned men around him, not just on marine fos-
sils, but also terrestrial ones. The latter were related to 
a ‘time of giants’ referrable to Scripture, a third biblical 
event with which to compare the fossil record, as it will 
be shown. The Book of Genesis in fact revealed that:

The giants were in the earth in those days, and also after 
that, when God’s sons were being entered toward the 
daughters of humans and they were begetting to them-
selves; those were the giants from the eons [greek αἰών] the 
humans of renown.67

67 Genesis 6, 4, from the Greek Septuagint Bible. See R. S. Hendel, “Of 
demigods and the Deluge: toward an interpretation of Genesis 6:1-4”, 
J. Bibl. Lit. 106, 1987, pp. 13-26. For an exploration of Protestant and 
Catholic attitudes towards the interpretation of this passage, see A. Hes-
sayon, ref. 6, pp. 5-40.

Figure 2. Copper engraving by Eisenhoit of a large oyster shell 
(‘Ostracites’) dug up from the earth at San Miniato (‘oppidi Miniati’; 
locality 3 in Fig. 1) and drawn by Mercati, published posthumously 
in 1717, but available to Steno in 1666. Photograph by Saulo Bambi, 
reproduced with permission, courtesy of the Botanical Library of 
the Florence University.

Figure 3. Slightly inclined fossiliferous strata at San Miniato (local-
ity 3 in Fig. 1; outcrop about 50 m-thick). Rich shell beds associ-
ated with large shark teeth have been studied here since the time of 
Leonardo da Vinci (1453-1519) to the present day. Photograph by 
the author.



68 Stefano Dominici

In Florence Steno was sustained by the esteem of 
newly-acquired learned friends, including renowned dis-
ciples of Galileo such as Vincenzo Viviani (1622-1703) 
and Francesco Redi (1626-1697).68 The sea of Tuscan 
coast offered plenty of living shelled marine animals to 
compare with fossils that were dug up in nearby hills. 
Bruno della Molara, a member of the court, testified that 
in the summer of 1667 Steno was studying living mus-
sels and discussing his view with others:

I am delighted by your progresses in the investigations of 
interesting matters, particularly of the mussels and I am 
even more pleased that you have made satisfactory obser-
vations which confirm your view.69

Among the Florentine academians was Giovanni 
Alfonso Borelli (1608-1679), one of the most gifted dis-
ciples of Galileo Galilei.70 The least friendly among the 
Medici courtiers, he helped Steno, providing knowl-
edge and fossils form Sicily. Steno had contacted him 
soon after his arrival in Tuscany, as a suspicious Borelli 
revealed in July 1667 in a letter to Marcello Malpighi (of 
the same Galilean circle):

I’m giving you the news that Steno is here, and that he 
shall remain the whole summer, and that he told me he 
wants to come to visit me, and that he wants me to teach 
him something about geometry etc. I won’t refrain from 
offering him all the courtesy possible, but I’m not so gul-
lible as to believe in the idea of modesty and good man-
ners in which he is proclaimed, because those little epis-
tles he has printed clearly hint at his avidity to absorb all 
the things, and put others in distress, and I know these 
foreigners come here to us well prepared, and willing to 
remain cautious, so that their cunning by far surpasses 
ours, with the result that in the end it will be us who will 
be submitted for long.71

The Italian network of learned men interested in 
Steno’s Canis Carchariae included Agostino Scilla in 
Sicily,72 collaborating with Borelli, Malpighi and John 

68 P. Galluzzi, in ref. 39 (Negri, Morello, Galluzzi), pp. 113-129.
69 For Bruno della Molara (1639-1685) see A. Cont, Dimensioni e proble-
mi della ricerca storica, 2011, 2, pp. 231-259. Letter (14 July 1667) quot-
ed in ref. 1 (K&M), p. 187. Another learned informant was Francesco 
Maria Florentini (1603-1673): G. Scherz, in ref. 1 (K&M), p. 182.
70 L. Boschiero, in Borelli’s On the movement of animals - On the force of 
percussion (Tr.: P. Maquet), Brill, Leiden, 1989, p. i-xxi. P. Galluzzi, ref. 
68.
71 G. A. Borelli, 17 July 1666, in M. Malpighi, The correspondance of 
Marcello Malpighi (Ed.: H. B. Adelmann), Cornell University Press, 
Ithaca-London, 1975, 1, pp. 318-319. Borelli was studying animal move-
ment, a subject dealt with by Steno at exactly the same time.
72 F. Giallombardo, Agostino Scilla (1629-1700) e la cultura visuale della 
historia, fra antiquaria e storia naturale, unpublished PhD thesis, Uni-
versità di Palermo, Palermo, 2016, pp. 71-72. 

Ray,73 and the physician Giovanni Battista Capucci from 
Crotone, in Calabria.74 The authority of Prince Leopold, 
accompanied by the general enthusiastic acceptance of 
Steno by the Medici Court, forced Borelli to submit and 
provide specimens from Sicily. In August he answered 
the Prince:

I send you two chunks of stone of the type produced by date 
shells [rock-boring mussels; …] I’ve commanded to bring 
you some piece of good stone, which no doubt will give the 
opportunity to philosophise.75

In two letters of October-December 1667, Borelli 
communicated with Prince Leopold about the inter-
pretation of marine and terrestrial fossils. These man-
uscripts not only testified to the whole court being 
involved in Steno’s research, but particularly revealed 
that larger fossil bones were interpreted as evidence of ‘a 
time of giants’, as mentioned in the Book of Genesis:

I also thought that those shells could have originated 
from the sea, but then I changed opinion. I will await for 
the fine discourses of these Gentlemen to ascertain for me 
the truth. In the meanwhile, I have written to friends in 
Palermo, Siracusa and other places to get me the so called 
Giants’ teeth, and those large petrified shells that are 
found at many places in Sicily […]  If Your Highness could 
send me the drawing of the skull of that African ox found 
in the Chiane [referring to the Chiana valley, locality 5 in 
Fig. 1] to know how big it is, I would be grateful. […] I 
will send to Livorno those teeth and shells that I am col-
lecting.76
I have received the drawing of the buffalo skull, or ox found 
in the Chiane, and it is indeed much larger than those 
that we see nowadays in Italy [see Fig. 4 for a similar fos-
sil coming from the same context]. If it came from Africa 
I couldn’t say, since I’m told that in that savage place you 
don’t find oxen of such an enormous size. Maybe in that 
time in Italy lived that race of a size larger than our [cat-
tle] given that as among both dogs and horses we find some 
that by large exceed others, and I can assure Your High-
ness that here we find certain limestones and human teeth 
the size of which must relate to a man at least 2.3 m tall. 
For you to get the exact proportion, I send with this letter 
a drawing of one of those teeth. The man who owns them 
is too jealous of these curiosities and I didn’t dare ask, even 
if he is a friend. I have moreover collected a large quantity 
of petrified shells, some of very large size, that I will send, 
as you commanded me to do, with the first vessel that sails 

73 P. Findlen, Science in the age of baroque (Eds. G. Gal, R. Chen-Mor-
ris), Springer, Dordrecht, 2013, p. 135.
74 G. B. Capucci, 25 July 1667, in ref. 40, pp. 352-352.
75 G. A. Borelli to Prince Leopold, 3 August 1667, in ref. 38 (MG), Gal. 
278, f. 42v.
76 G. A. Borelli to Prince Leopold, 4 October 1667, in ref. 38 (MG), Gal. 
278, f. 73r-73v.



69A Man with a Master Plan: Steno’s Observations on Earth’s History

to Livorno. When Mr. Steno will pass from here, I will see 
him and gladly serve him.77

The finding of fossils of ‘a man at least 2.3 m tall’ 
and the bones of animals larger than the modern cer-
tainly solicited Steno’s philosophical interest for links 
between observation of nature and Scripture. In July 
1668, Borelli informed the Prince that the vessel with its 
naturalistic cargo had shipwrecked and that he provid-
ed a new collection of fossils. Similarly to the first ship-
ment, it included ‘stones taken from mountains twenty 
miles far from the sea’78 and other geological specimens. 
Clearly, there was a keen interest for fossils at the Medici 
court in connection with Steno’s activities of 1667.

Specimens from Malta are not all wrapped in their stoney 
casing, but imagine them to be [originally] contained in 
the same soft stone in which you see the tongue stones, or 
teeth; these teeth, vertebrae and eyes are dispersed in black 
stone, some small some large [see Fig. 5] Such observations, 
and better ones, will be made over there by those illustrious 
philosophers, being myself humbly busy with laying down 
this book of mine on paper, in the hope to complete it in 
short time.79

We thus know that, at least since summer 1667 and 
while working at a larger dissertation on solids natu-
rally enclosed in other solids, Steno involved a group of 

77 G. A. Borelli to Prince Leopold, 1 December 1667, in ref. 38 (MG), 
Gal. 278, f. 95r-95v.
78 G. A. Borelli in ref. 38 (MG), Gal. 278, f. 95r-95v.
79 G. A. Borelli to Prince Leopold, 8 July 1668, in ref. 38 (MG), Gal. 278, 
195r-195v.

informed people in a fervent activity directed towards 
definitely proving that fossil shells and ‘tongue stones’ 
did not form inside the rocks, and thus verified their 
utility as a means to ‘philosophise’ on historical events. 
We can also reasonably speculate that ‘philosophis-
ing’ included a discussion of matters distinctly related 
with biblical events: remains of large terrestrial animals 
of African affinity provided information on a ‘time of 
giants’, while marine fossils, whether from Malta, Sicily 
or Tuscany, would mark the time when waters covered 
the land, ending the existence of ‘those races of a size 
larger than ours’ – in Borelli’s words.

5. EARTH’S HISTORY UNROLLED IN TUSCANY

In May 1668 Steno had informed Magalotti about 
his intention to complete a ‘treatise on the earth and 
the bodies found in it’, described as ‘a succinct, not to 
say disordered, account of the chief things that I have 
resolved to set down in the Dissertation itself, not only 
more distinctly, but also at greater length, with in addi-
tion, a description of the places where I have observed 
each item’. The final text was completed in August 166880 
after months of additional fieldwork traveling ‘from the 
Arno to the Tiber’ (that is, from Florence to Rome: he 
apparently never suceeded in moving farther south).

The Prodromus addressed some of the basic ques-
tions of natural philosophy: what is the nature of matter, 
what is movement, and what is the method to answer 

80 G. Scherz, in ref. 1 (K&M), p. 209.

Figure 4. Skull of a large ox dug up in Val di Chiana (width of 
horns about 105 cm); a similar specimen is mentioned by Borelli 
in letters to Prince Leopold. Photograph by Saulo Bambi, specimen 
reproduced courtesy of the Museum of Natural History, University 
of Florence.

Figure 5. Malta ‘large tongue stones’ (in the terminology used in 
1667) from unspecified ‘Old Museum collection’ (= ‘Antica Collez. 
del Museo’, written in the 19th century): similar specimens were 
sent by Borelli in 1667. Photograph by Saulo Bambi, specimen 
reproduced courtesy of the Museum of Natural History, University 
of Florence.



70 Stefano Dominici

these questions? More importantly, Steno took a clear 
position regarding Earth’s history, choosing the uni-
versal flood as the fulcrum of the discourse, the occur-
rence of which he could now clearly demonstrate. As far 
as the nature of Tuscany allowed, Steno’s method pre-
sented evidence of the other biblical events mentioned 
above, one concerning the third day of creation, when 
the Aristotelian element earth started to exist separated 
from water, another concerning the time when giants 
populated the Earth. To these he added in the Prodro-
mus a further biblical event, the repopulation of the 
planet, occurring after the deluge had swept away “all 
things which have the breath of life, and whatever was 
on the dry land” (Gen 7, 22). This repopulation, start-
ing from a handful of noachian survivors, soon spread 
all over the world following God’s command (“increase 
and multiply, and fill the earth and have dominion over 
it”: Gen 9, 1). Evidences of this were represented by the 
ruins of ancient civilizations, from the Etruscan in Tus-
cany, studied by Steno’s contemporary antiquarians and 
briefly presented in the Prodromus, to the Chinese in the 
Far East, then made popular by Martini’s chronicles (see 
above notes 40-41).

The first part of the book is methodological, abstract 
and complex, but worth the effort of reading – implies 
its author – because it promises to solve a problem of 
natural philosophy that troubled contemporary authors: 
‘namely the way in which marine objects had been left 
in places far from the sea’, a problem concerning ‘a kind 
of universal deluge’ (p. 6).81 In the first part of the book 
(pp. 6-23), Steno presented a new category of phenome-
na, ‘solids naturally contained in other solids’,82 bringing 
order to observations of different kinds: 

If one wishes to reduce solids enclosed naturally within sol-
ids to definite classes, by the above method, some of them 
will be found to have been produced by apposition from an 
external fluid, this refers either to sediments such as the 
strata of the earth […] or angular bodies […]. Other sol-
ids are produced through apposition from an internal flu-
id.’ […] ’ it will be easy, given the solid and its location, to 
make a definite statement about the place of its production. 
(p. 23)83 

The Prodromus then considered specific classes of 
solids, including ‘strata of the earth’ (pp. 26-28), explain-
ing the historical meaning of the regularly-stacked bod-
ies of turbidite sandstones that form large part of the 
Apennines. These are sedimentary strata characterised 

81 Numbers in brackets refer to pages in the original 1669 publication, 
translated in ref. 1 (K&M), pp. 621-660.
82 N. Morello, ref. 39, p. 79-80.
83 N. Stensen, Prodromus, in ref. 1 (K&M), pp. 632-633.

by sharp or erosive bases, tabular geometry (Fig. 6), 
good-sorting of the clastic component and sedimentary 
structures that indicate settling of particles while the 
water mass was still moving (Fig. 7). To Steno they were 
documents of the third day of creation, immediately 
before the separation of dry land from sea and when a 
‘universal fluid’ was all that there was.

Differences in layers at the same place can be produced 
either by the diversity of particles leaving the fluid in suc-
cession, as this fluid is gradually dissipated more and more, 
or by dif ferent f luids being conveyed there at dif ferent 
times: so it happens that sometimes the same arrangement 
of layers is repeated in the same place, and often evident 
signs exist showing the ingress of new material. (p. 26)
If all particles in a stony stratum are observed to be of the 
same nature and of fine size, it cannot reasonably be denied 
that this stratum was produced at the time of Creation from 
a fluid that then covered all things; Descartes, too, accounts 
for the origin of the earth’s strata in this way. (p. 28)84

The signif icance of these primordial strata is 
enriched by their association with widely-separated 
‘high mountains’ (the Apennines). This fact proved that 
on the dawn of the third day of creation a fluid covered 
all things, as explained at the end of the book: 

That there was aqueous fluid, however, at a time when ani-
mals and plants had not yet appeared, and that the fluid 

84 N. Stensen, Prodromus, in ref. 1 (K&M), pp. 635. Steno refers to René 
Descartes’ Principia Philosophiae (1644), containing rather a model of 
the Earth, than an account of its history: see M. J. S. Rudwick, ref. 7, 
pp. 55-59.

Figure 6. Inclined, unfossiliferous strata of ‘Macigno’ sandstone at 
the historical Monte Ceceri quarries (outcrop about 20 m-thick, 
locality 1 in Fig. 1; similar strata occurred at the Gonfolina quar-
ries, locality 2 in Fig. 1). Strata are bounded by surfaces that once 
were ‘parallel to the horizon’, to use Steno’s words (Canis carchariae 
dissectum caput, written in 1666). Photograph by the author.



71A Man with a Master Plan: Steno’s Observations on Earth’s History

covered everything, is proved conclusively by the strata of 
the higher mountains which are free from all heterogeneous 
material; the outline of these strata testifies to the presence 
of a fluid; their material bears witness to the absence of 
heterogeneous bodies; the similarity in materials and out-
lines of strata from different mountains that are widely sep-
arated proves indeed that the fluid was universal. (p. 73)85

By ‘heterogeneous material’ he meant the petri-
fied remains of ancient living beings (see below). All 
three passages stress sorting of the particles that form 
the sedimentary bed and their origin by settling from 
a fluid (Fig. 7). An explanation of their actual position 
on ‘higher mountains’ as the key to infer the universal-
ity of the primordial fluid, had been anticipated in Canis 
Carchariae  (without specifying if in relation to the first 
flood, when solid matter separated from the universal 
fluid, or the second universal flood, when all breathing 

85 N. Stensen, Prodromus, in ref. 1 (K&M), p. 654.

creatures living on land were wiped out) where earth-
quakes had been called into action:

No weight should be attached to the arguments set out by 
people when they say that bodies of this kind ought to be 
found everywhere if they owe their existence to the waters 
covering all places, or at least, that such bodies when 
found, should not be found only in high places. […] It 
would be easy, to show how great are the changes in soil 
caused frequently by earth movement.86 

Other classes of solids included ‘mountains’ (pp. 
32-34) and ‘angular bodies’, or crystals in modern terms. 
Here he informs us that ‘the majority of the miner-
als with which human effort is engaged did not exist 
from the beginning of things’ (p. 44). By exclusion, the 
third day of creation, when solid earth first formed, is 
still documented in the natural world by some surviv-

86 N. Stensen, Canis Carchariae, in ref. 1 (K&M), p. 587-588.

Figure 7. Turbidite sandstone of the Macigno Fm (detail of one of the strata in Fig. 6), showing sedimentary structures (Monte Ceceri 
quarries, near Fiesole; locality 1 in Fig. 1; coin for scale: 22 mm). Finer-grained particles have settled above coarse-grained ones as a fluid 
transports them in ripples, in light colour, finally giving way to mud deposition, in dark colour. Stratal surfaces are parallel one to another 
(Fig. 6), but all are inclined with respect to the horizontal, meaning they have been titlted after their deposition. Photograph by the author.



72 Stefano Dominici

ing mineral. He was possibly thinking of the minutest 
clasts that make up turbidite sandstones of the Appen-
nines – although no evidence of this thought exists, but 
of course not including the largest and youngest crystals 
quarried at that time in Tuscany. For their size, these 
formed the object of Steno’s long discussion of geometric 
properties of regular solids, in pages that have attract-
ed the attention of historians of mineralogy and which 
formed a long digression in the central part of the book 
(pp. 37-53).

Also at the core of the book (pp. 53-61) is the dis-
course on organic fossils. Evidence of their marine ori-
gin included a comparison between modern animals 
and fossils he had seen in Tuscany, including Borel-
li’s specimens, with fossils embedded in their matrix. 
Steno’s 1666 interest in demonstrating that glossopetrae 
were shark teeth is not repeated in the Prodromus. Their 
heuristic role as proof of the marine origin of the sedi-
ments in which they were found, hence proof of the bib-
lical flood, is completely substituted in the Prodromus by 
the much more ubiquitous shelled molluscs. Examples 
abound, while he recalls shark’s teeth only in passing:

There are shells of oysters, of remarkable size, in which 
are found several oblong, worm-eaten cavities [Fig. 2] in 
all respects similar to those that are inhabited by a certain 
type of shellfish in the rocks of Ancona, Naples and Sicily. 
[…] In lumps of earth brought here from Malta, besides 
various teeth from various sharks, are found also various 
shellfish, so that if the number of teeth persuades us to 
ascribe their production to the earth, the construction of 
the teeth and their abundance in each animal, the similar-
ity of the earth to the sea bed, and the other marine bodies 
found in the same place favour the opposite opinion.87

Then he turns to remains of terrestrial animals and 
affirms his trust on the biblical account of the same evi-
dence:

For others, difficulty arises from the size of the femurs, cra-
nia, teeth, and other bones that are dug from the earth; 
but there is not much either in this objection that unusual 
size should suggest a method beyond the powers of nature, 
since:
1. In our age, men of very large stature have been observed.
2. It is certain that there existed at one time men of gigan-
tic size.
3. Often the bones of other animals are mistaken for the 
bones of human beings. 
4. To attribute to nature the production of truly fibrous 
bones is on a par with saying that nature can produce the 
hand of a man without the remainder of the man. (p. 62)

87 N. Stensen, Prodromus, in ref. 1 (K&M), pp. 650-651.

The statement ‘It is certain that there existed at 
one time men of gigantic size’ is a reference to Borelli’s 
gigantic ‘human teeth’ and to the ‘time of giants’ nar-
rated in Genesis 6, 1-4 – again, Steno obviously had the 
Bible in mind – while his familiarity with fossil bones 
and teeth of terrestrial animals echoes Borelli’s inputs 
on the lack of modern analogues of the bones of the 
‘Chiana’ gigantic ox (Fig. 4) and other large animals. In 
analogy with marine remains, terrestrial ones (including 
plants, pp. 65-67) were associated with fluvial conglom-
erates. These abound in the upper Arno valley and other 
places between Florence and Arezzo (for example local-
ity 5 in Fig. 1) and prompted yet another vision of solid 
particles moved by a liquid.

The place from which the said bones are dug was built up 
from various strata that are filled with stones rolled down 
from the surrounding mountains by the force of torrents. 
(p. 65)88

The series of proofs of the unrolling of events that 
match the biblical narrative is completed by the geologi-
cal description of the hill upon which the town of Vol-
terra is built (locality 4 in Fig. 1). In this section Steno 
merges observation of nature with antiquarianism and 
historical accounts, trusting the authority of classic 
authors, as he had done two years before in Canis carch-
ariae. Most important, this is also the point he introduc-
es absolute time in the narrative, adopting the language 
of the chronologists that measure the number of years 
that have elapsed between some key events, albeit in 
Steno this takes the form of rough estimates. It is worth 
recalling here the obvious, that the science of chronolo-
gy was essentially biblical, although not only biblical, as 
exemplified by the Prodromus itself. Earth’s history was 
only a few days longer that human history, but a suffi-
ciently long stretch of time to fit all the events that mat-
tered, according to an average 17th century thinker.89

There are those to whom the length of time seems to destroy 
the force of the remaining arguments, since there are no 
recollections in any age to confirm that floods have risen 
to the places where many marine bodies are found today, if 
the universal deluge is excepted, from which time it is esti-
mated that 4000 years have elapsed up to the present.90
It is certain that before the foundations of the city of Rome 
were laid, the city of Volterra was already powerful; but 
shellfish of every kind are found in the huge stones that are 
found in certain places there. […] The whole hill on which 
the oldest of the Etruscan cities is built rises from marine 

88 N. Stensen, Prodromus, in ref. 1 (K&M), p. 652.
89 M. Rudwick, ref. 7, pp. 9-23; A. Grafton, ref. 41.
90 N. Stensen, Prodromus, in ref. 1 (K&M), pp. 651-652.



73A Man with a Master Plan: Steno’s Observations on Earth’s History

sediments, laid on top of other, parallel to the horizon, in 
which there are many non-stony strata which abound in 
true molluscs that have suffered no change in any way, and 
so it is possible to say with certainty that the unchanged 
molluscs that are extracted from them today were produced 
more than 3000 years ago. From the founding of the city 
to the present day we reckon more than 2420 years have 
elapsed; and who will not grant that many centuries have 
elapsed since the first men transferred their homes there 
until it grew to the size that flourished at the time of the 
founding of the city? If we add to these centuries the time 
which elapsed between the laying down of the first sedi-
ment of the hill of Volterra and the withdrawal of the sea 
from the same hill, when strangers flocked to it, we shall 
easily go back to the time of the universal deluge. (p. 
63-64)91

The final section of the Prodromus (pp. 67-76) strict-
ly concerns the fit betwen events inductively demonstra-
tated for Tuscany and those narrated in the Bible. They 
are preceded by a sentence that perhaps justified the 
opinion that Steno was aware of consequences from the 
Church: ‘But lest anyone be afraid of the danger of nov-
elty etc.’ On the other hand, judging from the fact that 
for Steno biblical history was history tout court, these 
closing passages appear a summary of what he had final-
ly proved, proud to announce the coherency of the mar-
vellous plan of God. Their content had been forewarned 
in the introductory chapter:

The fourth part describes various conditions of Tuscany not 
dealt with by historians and writers on things of nature, 
and proposes a kind of universal deluge that is not rejected 
by the laws of natural movements. (p. 6)92

Accompanied by the now-famous schematic draw-
ing of the six periods during which the present Tus-
can relief took shape,93 the final part of the Prodromus 
is a counterpoint between the voices of the scripture 
and nature, the former proposing, the latter answering 
(whenever possible), sometimes both remaining silent. 
Steno’s discussion of his six periods revealed the final 
purpose of the dissertation and of all his commitment 
to the study of fossils, crystals and rocks, and retrospec-
tively the climax of a lifetime search for truth: not to 
found a new science (‘geology’), but to reconcile philoso-
phy and theology, physics and metaphysics: 

How the present state of anything discloses the past state 
of the same thing is made abundantly clear by the exam-

91 N. Stensen, Prodromus, in ref. 1 (K&M), pp. 651-652.
92 N. Stensen, Prodromus, in ref. 1 (K&M), p. 625.
93 S. J. Gould, Hen’s Teeth and Horse’s Toes: Further Reflections in Natural 
History. New York, Norton 1983, 413 pp.

ple of Tuscany, above all others. […] With regard to the 
first aspect of the earth, scripture and nature agree in this 
respect, that everything was covered with water; but of how 
and when it began, and how long it lasted as such, nature 
says nothing, while scripture speaks. […] at the time when 
the strata of unmixed material, obvious in all mountains, 
were being formed, the rest of the strata did not yet exist, 
but everything was covered with a fluid devoid of plants, 
animals, and other solids. Since no one can deny that the 
strata are of the kind that could have been produced imme-
diately by the First Mover, we recognize from this the obvi-
ous agreement between scripture and nature. (p. 70)
About when and how the second aspect of the earth, which 
was flat and dry, began, nature is likewise silent, while 
scripture speaks […]
When the third aspect of the earth, which is believed to 
have been uneven, began, neither scripture nor nature 
determines; nature shows that the unevenness was of some 
magnitude; scripture, moreover, mentions mountains at 
the time of the deluge; as to the rest, neither scripture nor 
nature determine when those mountains, of which scripture 
makes mention, were produced […] reason persuades us 
that, in the first centuries of the world’s existence, cavities 
were gnawn out by water and by fire, so that slighter col-
lapses of strata followed from this. […]
The fourth aspect, when all was ocean, seems to cause more 
difficulty, although in truth it is not difficult. The produc-
tion of hills from marine deposits testifies that the sea 
was higher than it is now, and this not only in Tuscany 
but also in very many places far enough from the sea […] 
If the activity of a living creature can bring it about that 
sometimes places flooded with waters are made dry by its 
decision, and sometimes are flooded with new waters, why 
should we not willingly concede to the First Mover of all 
things the same freedom and the same powers? With regard 
to the time of the universal deluge, sacred History, review-
ing everything in detail, is not opposed by secular history. 
The ancient cities of Tuscany, some of which are built on 
hills produced by the sea, were founded more than 3000 
years ago; in Lydia, however, we come nearer to 4000, so 
that it is possible to reckon from this fact that the time at 
which the earth was abandoned by the sea is in accord-
ance with the time of which scripture makes mention. […] 
nature does not contradict what scripture determines about 
how high the sea was. (p. 72)94

Steno was finally asserting in the Latin language 
directed not just to his Italian readers, but to the whole 
European community of learned men, that a universal 
principle of geometry, perfectly entrenched in the new 
philosophy, confirmed biblical facts. This would have 
helped to silence unorthodox thinkers and re-assert 
the supremacy of a literal reading of the biblical text. If 
Steno’s sensibility had been shaken by criticism towards 
standard chronology, alive in certain cultural circles, 

94 N. Stensen, Prodromus, in ref. 1 (K&M), pp. 653-655.



74 Stefano Dominici

biblical references in the Prodromus were more than a 
tribute to religion by a Catholic convert. They formed 
instead the conclusion of a philosophical and theological 
journey in the search for ‘true religion’ that had com-
menced before travelling to Tuscany. His reasoning gave 
a final sense to a long study to find the meaning of fos-
sils shells and ‘tongue stones’.

6. AFTER THE PRODROMUS

In the same year of the publication of the Prodro-
mus, Steno continued to carry out geological fieldwork 
in the light of his theory, as testified by a letter written 
in October 1669 after visiting quarries in Hungary (pre-
sent day Slovakia), a new occasion to study the rocks 
produced during the time of the first ‘universal fluid’.

My journey to visit the quarries caused me great happiness 
not just for the novelty of the observations, which were very 
few, but for the autopsy of those things, that upon read-
ing metallic authors are understood with much difficulty. I 
have seen nonetheless something consistent with my opin-
ions on the transformations that the earth underwent, 
inasmuch that in the same places soils of Macigno are 
inclined with respect to the horizon, so that in that place 
cannot have been materially made.95

The letter proves that the method exposed in the 
Prodromus, nicely expressed with borrowed words from 
the anatomist (‘the autopsy of those things’), was once 
again applied with success, this time to strata observed 
outside of Italy.

The science inaugurated by Steno relied on the 
observation of nature and on concordance with Scrip-
ture. The attempt at reconciling inconstistencies occu-
pied learned men96 and missionaries, particularly 
among the Jesuits including in 1667 Athanasius Kirch-
er.97 Debates such as this continued into the eighteenth 
century, while a steadiliy increasing number of savants 
across Europe presented new theories of the Earth, and 
skepticism towards biblical chronology reached fur-
ther.98 Earth as sketched in the Prodromus looked much 

95 N. Stensen to M. Malpighi, 27 October 1669, in ref. 40 (Adelman), 
p. 429-430. ‘Metallic authors’ referred to the work of late Renaissance 
learned men like Michele Mercati. ‘Macigno’ refers to a particular type 
of sandstone quarried near Florence. This is devoid of fossils and thence 
to Steno it is the material evidence of the third day of Creation.
96 Debates among Protestants in the Dutch Republic were fierce, while 
chronologists contemporary to Steno investigated “the nature of ancient 
and modern, eastern and western calendars and established the dates of 
great events”: A. Grafton, ref. 41, p. 45.
97 R. Rappaport, ref. 5, pp. 77-79. A. Ziggelaar in ref. 2 (Rosenberg), p. 140.
98 R. H. Popkin, A. J. Vanderjagt, Scepticism and irreligion in the seven-
teenth and eighteenth centuries, Brill, Leiden, 1993, 373 p.

like the model introduced by Descartes in his Principiae 
Philosophiae of 1644, with its inner cavities justifying 
the collapse of originally-concentric sedimentary strata 
at its surface.99 But Descartes despised history,100 while 
Steno searched different sources, both textual and natu-
ral, the latter based on geometry. Few contemporary nat-
ural philosophers were equipped with Steno’s experience 
of the natural world, many distintly favouring the study 
of annals and biblical scholarship, with a penchant for 
establishing systems often disconnected from empirical 
evidence. Despite not having Steno’s experience in the 
natural world, most still accepted Scripture and classic 
authors as trustworthy sources.

Among contemporary authors, the Sicilian painter 
Agostino Scilla (1639-1700; see above note 72) had stud-
ied a very large variety of marine fossils and their sedi-
mentary context, as he demonstrated in his La Vana 
Speculazione Disingannata dal Senso of 1670. Himself 
creator of  the wonderful engravings that illustrated his 
book, rivalling those of Eisenhoit used by Steno, Scilla 
did not cite the Dane. However, he surely knew Canis 
Carchariae through Borelli and Malpighi, academi-
cians with whom he was connected in Sicily. Similarly to 
Steno, Scilla interpreted marine fossils as evidence of the 
biblical deluge, seeking further evidence for his interpre-
tations in the work of classical authors and antiquari-
ans.101

Robert Hooke (1735-1703)102 authored a rudimentary 
theory of the Earth in 1668 based on Steno’s hypothesis 
of 1667 that most fossils originated in the sea, but dis-
missing the Flood as the cause, invoking in its place the 
action of earthquakes. The latter he called into action, 
together with other natural causes, to also explain other 
biblical episodes, such as the time of giants, while pay-
ing close attention to contemporary biblical scolar-
ship.103 In his 1715 theory of the Earth, the astronomer 
Edmond Halley (1656–1742), of the same Baconian circle 
as Hooke, still relied on chronology in  Genesis, however 
more critically interpreted.104

Steno’s lesson certainly informed the other great 
contemporary philosopher and pioneer in the study of 
the Earth, the German polymath Gottfried Wilhelm 

99 M. J. S. Rudwick, ref. 7, pp. 55-56.
100 R. Rappaport, ref. 5, pp. 64-65; M. J. S. Rudwick, ref. 7, p. 55.
101 P. Findlen, ref. 73, pp. 119-159.
102 British natural philosopher, active in Montpellier at the time of 
Steno’s residence there, and one of the founding members of the Royal 
Society in London, Hooke deciphered the organic origin of fossils as 
early as 1663, publishing the idea in his Micrographia (1665): T. Yama-
da, in ref. 2 (Rosenberg), pp. 107–126.
103 W. Poole, ref. 4, pp. 43-49; K. Birkett, D. Oldroyd, The Uses of Antiq-
uity (Ed. S. Gaukroger), Springer, Dordrecht, 1991, pp. 145 – 170.
104 W. Poole, ref. 4, pp. 45-46.



75A Man with a Master Plan: Steno’s Observations on Earth’s History

Leibniz (1646-1716). Leibniz had met Steno more than 
once between 1677-1680 and the history of the world, 
the main theme of the Protogaea that the German would 
complete in 1693, formed the object of their discussion. 
Leibniz, deeply influenced by the Dane,105 left the clear-
est testimony of the primary significance that the full 
Dissertation on solids was meant to have for contempo-
rary philosophers:

I have often incited him [Steno] further to carry them out 
[geological studies] and to draw from them conclusions to 
find out the origin of the human kind, the general water 
flood and some other nice truths which would confirm 
what the Holy Scripture tells of that.106

All of the above authors, and others, were evidently 
influenced by Steno. With them, evidence that biblical 
scolarship genuinelly informed the work of early modern 
men of science is therefore ample. They were still natural 
philosophers, not geologists, but their science was for the 
first time driven by the observation of nature, to which 
they adapted the authority of preceding authors. In this 
important phase of the history that eventually led to 
modern geology during the last quarter of the eighteenth 
century,107 Steno was the first to publish a history of the 
Earth based on the study of fossils and sedimentary stra-
ta, albeit in the summary form to which he felt pressed 
by a variety of factors. We can still comment on today 
the fact that Steno accepted an age of the Earth incon-
ceivable by modern standards, but this should in no way 
influence our understanding of his role in the history of 
science.

7. CONCLUSIONS

Nicolaus Steno’s contribution on the study of the 
Earth, passed on to us through two published essays of 
1667 and 1669, looks to the relationship with contem-
porary culture and with the transnational society of 
learned men to which he belonged. Steno and his con-
temporaries shared the belief that the Bible was an his-
torical book, and that the Book of Genesis constituted 
a means to learn about the early part of Earth’s history. 
Steno thought that his work as a natural philosopher 
could find in nature evidence for the mysteries of crea-
tion. It is evident that Steno took Scripture as a guide 
to comprehend the structure and composition of the 

105 C. Cohen, A. Wakefield, Protogaea, by W.G. Leibniz, University of 
Chicago Press, Chicago & London, 2008, pp. xiii-xlii.
106 G. W. Leibniz, quoted in ref. 1 (K&M), p. 226; see also F. Sobiech, in 
ref. 2, p. 181; D. Garber, in ref. 13 (A&L). 
107 M. J. S. Rudwick, ref. 7, pp. 79-127.

earth beginning with his student years in Copenhagen, 
Amsterdam, and Leiden, in his subsequent explorations 
of the Tuscan region, and in his readings of and inter-
actions with fellow natural philosophers at the Medici 
Court. In Tuscany he perfected a method that allowed 
him to reconstruct historical events independently, but 
consistently with Scripture. This method was based on 
the application of simple geometric principles to the 
study of different types of geological objects, from crys-
tals and fossils, to rocks and strata, and on to moun-
tains and the whole Earth. Evidence in his writings from 
1659-1669 is consistent with an interest to carry out an 
anatomy of the Earth nurtured through the years, partly 
hidden by the primary interest in the anatomy of animal 
and human bodies.108 It is also hypothesised that this 
was one of the reasons for travelling to Tuscany where 
he could carry out the necessary field work within the 
right cultural milieu. Steno was a meditative man whose 
anatomical studies had significance inasmuch they dis-
closed the immense wisdom displayed by God in creat-
ing the world. The consistency of his study of the Earth 
with the narrative of Scripture would have blunted criti-
cism of the skeptics, reinforcing the authority of the 
Bible.

ACKNOWLEDGMENTS

I thank reviewers Eric Jorink and Jacob Bek-Thom-
sen for providing thoughtful and constructive feedback, 
which was very helpful in improving the manuscript. I 
thank Gary D. Rosenberg who edited the paper many 
times, helping to focus and correcting the English with 
much patience, and Nuno Castel-Branco, for discussing 
aspects of Steno’s achievements and sharing his knowl-
edge of Stenonian primary and secundary literature.

108 The connection between anatomy and the idea of landscape is 
explored by Rosenberg, G.D., “An artistic perspective on the continui-
ty of space and the origin of modern geologic thought”, Earth Sciences 
History, 2001, 20, 127-155; G. D. Rosenberg, “The measure of man and 
landscape in the Renaissance and Scientific Revolution”, in The Revolu-
tion in Geology from the Renaissance to the Enlightenment (Ed.: G. D. 
Rosenberg), Geol. Soc. Am. Mem., 2009, 203, 13-40.