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Byzantine heavy artillery: The Helepolis
Dennis, George T
Greek, Roman and Byzantine Studies; Spring 1998; 39, 1; ProQuest
pg. 99

Byzantine Heavy Artillery: The Helepolis 

George T. Dennis 

THE MILITARY MANUAL (Strategikon) attributed to the 
emperor Maurice stipulated that the infantry contingents 
should be followed by a train of wagons, some of which 

were to transport artillery crews, carpenters, and metal 
workers, as well as ~aA.A.i(J'tpUl; £Ka'tEpro9Ev (J'tPE<pOJ.l£va<;.l In 
his translation accompanying the Greek text E. Gamilscheg 
rendered this as "Katapulten nach beiden Seiten zu drehen." I 
put it into English as "revolving ballistae at both ends."2 I 
visualized the wagons as mobile fighting platforms with two 
medium-sized torsion or tension weapons, ballistae, which re­
volved in a horizontal arc, somewhat like pivoting machine 
guns. "Both ends," though, I am now convinced, refers to the 
weapon, not the wagon, and the revolving motion must have 
been vertical, up and down (like a child's seesaw), not hori­
zonta1.3 Torsion weapons, such as the ballista, do not revolve; 

1 Das Strategikon des Maurikios, ed. G. T. Dennis, trans!' E. Gamilscheg 
(CFHB 17: Vienna 1981) 12.B.6.9. 

2 Maurice 's Strategikon. Handbook of Byzantine Military Strategy, trans!' C. 
T. Dennis (Philadelphia 1984) 139. 

3 It is possible, but unlikely, that the author is referring to the carroballista 
of Vegetius which was mounted on a small horse-drawn cart (Epitoma rei 
militaris, ed. and transl. L. Stelten [New York 1990] 2.25, 3.24), or to the 
swivelling bolt-projecting catapult, also mounted on a cart, described by the 
Anonymus, De rebus bellicis, ed. R. Ireland (Oxford 1979) 18. But there is no 
evidence that field artillery of this sort lasted into the sixth century. It is also 
possible, though again I believe unlikely, that the passage refers to twisting the 
springs of the two arms of a torsion catapult: E. W. Marsden, Greek and Roman 
Artillery: Technical Treatises (Oxford 1971) 44, 123, 131-135, 169-173. 

Greek, Roman, and Byzantine Studies 39 (1998) 99-115 
© 2000 GRBS 

99 



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100 BYZANTINE HEAVY ARTILLERY 

the onager, which pivots from down to up, moves only at one 
end. The Strategikon, I would argue, is not referring to a torsion 
or tension weapon at all, even though it uses the classical word, 
ballista, but to a more advanced kind of artillery, recently 
arrived in the Mediterranean world, which was operated by 
traction, men pulling ropes at one end of a rotating beam to 
propel a projectile placed in a sling at the other end, thus 
"revolving at both ends." There was as yet no specific term for 
this artillery piece, but it later came to be known in the west as 
trebuchet and, as we shall see, very soon in the Byzantine world 
as helepolis (city-taker) . 

This thesis seems to be confirmed by the Tactical Constitutions 
of Leo VI, compiled at the beginning of the tenth century, and 
which, to a large extent, was intended to bring previous military 
manuals into line with contemporary equipment and termin­
ology. According to Leo, the wagons accompanying the infantry 
were to carry 'to~opoAi(j'tpu~, that is, torsion or tension 
weapons, and a supply of bolts. In addition, they were to carry 
"ballistae or machines called alakatia which revolve in a circular 
manner," pUAi(j'tpu~ ~'tOl JlUYYUVlKel 'tel AqOjlEVU UAuKCtnu 
(j'tPEq>OjlEVU KUKt..o8EV (6.27). 4 

The old word, ballista, is copied from the Strategikon but then 
further qualified as alakatia. This is another generic Byzantine 
word, aAuKanov, a diminutive of TJAUKa'tTl, which can desig­
nate a distaff or distaff-shaped object, the upper, revolving 
part of a mast, a windlass, or any staff-like object designed to 
turn. The JlUYYUV1Kel aAuKanu mentioned by Leo "revolve at 
both ends, in the two parts, or in a circle," Exu't£pco8EV, d~ 't<l 
8uo jlEpTJ, KUKA08EV, yUpC08EV. 5 Clearly, these are stone-throw­
ing machines, 1tE'tPOPOAU jlUYYUV1KCt, which could also launch 

4 Ed. R. Villi, Leonis imperatoris Tactica, libri I-XIV (Budapest 1917-1922) 
38 (complete in Migne, PG 107.669-1120). On the changing meaning of hal/isla 
see N . Petrin, "Philological Notes on the Crossbow and Related Missile 
Weapons," GRBS 33 (1992) 265-291. 

55.6, 6.27; Recensio Const. ad loc. 



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GEORGE T. DENNIS 101 

incendiary missiles.6 The fact that they revolved at both ends or 
in a circular fashion makes it almost certain that these alakatia 
were trebuchets, very likely pole frame models which could be 
transported in wagons, quickly assembled, and operated by one 
or a few soldiers, much as depicted in the illustrated Madrid 
Skylitzes.7 Later, in the tenth century, Nikephoros Phokas 
ordered that each unit of light infantry was to have access to 
three of these alakatia, along with other portable artillery.8 

The author of the Strategikon does not tell us when this new 
kind of artillery was introduced into the Byzantine Empire, but 
the historian of Maurice's reign, Theophylaktos Simokatta, does 
provide information about when it came into use and what 
name the Byzantines gave the new weapon. Bousas" a Byz­
antine soldier captured by the A vars, taught them how to 
construct a siege machine (1tOAtOPK1ltlKOV 'tl JlllXavTWcx), for 
they were ignorant of such machines (opyav())v). And so he 
prepared the helepolis to shoot missiles: aKpo~OAisEtv ... 't1-!v 
EAf1tOAtV (2.16.10).9 With this fearsome and skillful device 
(OEtVQV 'tExvOUPYllIlCX) the Avars attacked many Byzantine 
cities, leveling the fortress of Appiareia in 587 and ten years 
later attacking Thessaloniki, which successfully resisted 
(2.16.11, 2.17.2). Bousas, and other Byzantine artillerymen, 
therefore, must have learned how to build and operate these 
weapons some years before 587. 

The fear and destruction wrought by these trebuchets, fifty 

615.27; cf Strategikon 10.1.52. 
7Fols. 151, 166, 169: S. Cirac Estopaftan, Sky/itzes Matriten sis I repro­

ducciones y miniaturas (Barcelona/Madrid 1965) 357, 369, 371; A. Grabar 
and M. Manoussacas, L'illustration du manuscrit de Skylitzes (Venice 1979) 
figs . 193,213. 

81.15; text in E. McGeer, Sowing the Dragon's Teeth: Byzantine Warfare in 
the Tenth Century (Washington 1995) 20. 

9 Theophylacti Simocattae Historia, ed. C. de Boor (Leipzig 1887) 102-103. 



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102 BYZANTINE HEAVY ARTILLERY 

of which were deployed against Thessaloniki, is vividly de­
scribed in the Miracula S. Demetrii: lO 

These were tetragonal and rested on broader bases, tapering to 
narrower extremities. Attached to them were thick cylinders 
well clad in iron at the ends, and there were nailed to them 
timbers like beams from a large house. These timbers had the 
slings from the back side and from the front strong ropes, by 
which, pulling down and releasing the sling, they propel the 
stones up high with a loud noise. And on being fired they sent 
up many stones so that neither earth nor human constructions 
could bear the impacts. 

The defenders also made use of stone-throwing machines, 
1tetpap£at, to fire back at the Avaro-Slav artillery (I 187.21). 
Sailors on the ships bringing supplies to the city were said to be 
experienced operators of these petrareai. The enemy is reported 
to have moved up to the walls certain engines of twisted wicker, 
nva EK A:uY01tA£K'!(()V opyava, and petrareai. ll Elsewhere the text 
speaks of both helepoleis and petroboloi, but the distinction 
between them is not clear (I 148.27, 152.10). 

Byzantine authors tend to use generic terms, so that artillery 
and other siege equipment are referred to simply as stone-throw­
ers, machines, engines, siege machines: 1tE'!po~6Aa, Ateo~6Aa, 
1tOAtOpKll'!lKa, IwyyavlKa, opyava, ll11xavai. As a result, it 

lOp. Lemerie, Les plus anciens recueils des Miracles de Saint Demetrius et la 
penetration slaves dans les Balkans I (Paris 1979) 154; the translation is taken 
from S. Vryonis, "The Evolution of Slavic Society and the Slavic Invasions in 
Greece," Hesperia 50 (1981) 384. There is some dispute about the date, some 
scholars putting the attack ten years earlier, but that need not affect our 
discussion here. 

11 1214.23. In 713/4 petrareai were positioned on the towers to strengthen 
the defenses of Constantinople: Theophanes Chronographia, ed. C. de Boor 
(Leipzig 1883) 1384.11-12. The tenth-century treatise on withstanding a siege 
prescribes hurling stones at the enemy, using petrareai, machines, and alakatia 
(AEKn'twv): De obsidione toleranda, ed. H . van den Berg (Leiden 1947) 56.6. 
ltEtPCXPE<lt is sometimes written tEtpnpEcxl. If this is not simply a scribal error, 
it could possibly be derived from tetra-, that is, a four-legged or trestle-framed 
trebuchet. AUYOltAEK'tOOV can refer to wicker roofs for tortoises or rams, or it 
could also mean several wooden spars bound together to form the flexible 
rotating beam of a trebuchet. 



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GEORGE T. DENNIS 103 

cannot be proved that a stone-throwing machine always means 
a trebuchet. In Classical usage, helepolis designated a movable 
siege tower, the invention of which or, at least, its first recorded 
effective use can be dated to 307 B.C., but except for a few 
archaizing passages, it is never so used by later Greek authorsY 
In addition to the generic 1tUPYo~, the Byzantine word for such a 
tower was Ilocruv. The tenth-century Sylloge Tacticorum clearly 
states that Ilocruv was the term preferred by writers on 
tactics.13 The fact that Anna Komnene employs this technical 
term several times indicates that she was well informed on 
military matters.14 Still, some ancient authors, such as Josephus, 
defined helepolis as a battering ram, and it is used in that sense 
once by Leo the Deacon in the tenth century: "The Romans," by 
which he must mean the ancient Romans, "call this device a 
ram. illS It seems that helepolis was often used to designate 
what was regarded as the most powerful siege weapon of its 
time, whether a tower, a ram, or a catapult. In Byzantine usage, 
however, helepolis, as will be clear in the following pages, 
almost invariably means a stone-throwing trebuchet. 16 In this 

12 Diod. 20.48; Plut. Oem. 21; see also 1 Macc. 43-44. The tenth-century 
writer on siegecraft twice describes a helepolis as a movable tower but, in 
both cases, he is drawing on earlier sources: D. F. Sullivan, Siegecraft: Two 
Tenth-Century Instructional Manuals by "Heron of Byzantium" (Washington 
1999) 106.38,114.5. Let me here express my thanks to Dr Sullivan for his help­
ful suggestions about technical terms. Procopius pictures a fighting platform on 
top of an elephant as a sort of live helepolis approaching the walls: Goth. 
8.14.35. 

1353.8; ed. A. Dain (Paris 1938) 102. In Classical Greek l-1ocrcr\Jv meant a 
wooden house, tower, or palisade. 

14Anne Comnene Alexiade, ed. B. Leib (Paris 1937-1943), hereafter An. 
Komn. (references are to book, chapter, section, then volume, page, line): 4.1.1 (1 
144.2),4.4.5 (1153.4, 11),4.5.1 (1154.11), 11.1.4 (III 9.21), 11.1.6 (III 10.13), 
13.3.9 (III 98.5), 13.3.11, 12 (III 99.3, 12, 15,30). 

lSJoseph. BJ 3.230.2, 5.279.4, 6.23.1, etc.; Leo Diac. 2.7 (p.25.13 Bonn). 
16The first scholar to point this out was Paul Chevedden, "The Invention 

of the Counterweight Trebuchet," forthCOming in DOP 54, to whom I am 
greatly indebted for getting me started on this article and for his many 
criticisms and suggestions. On western terminology see his "The Artillery of 



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104 BYZANTINE HEAVY ARTILLEFlY 

article, I simply transliterate helepolis when it occurs in the 
sources in order to emphasize its proper meaning; ordinarily, 
though, it should be translated as trebuchet. One also finds the 
adjective €A.E1tOA.1KO<;, as well as the verb €A.E7tOA.£W, "to take by 
means of helepolis." For example, Thomas the Slav led his 
armies over into Thrace to take Byzantium with helepoleis, 
€A.E1tOA.E1V 'to Busav'tlov.17 

This use of helepolis to mean trebuchet is found as far back 
as Simokatta, in the seventh century; in addition to the passage 
cited above, he writes of a Byzantine attack on a Persian 
fortress situated on a height. 18 Herakleios ordered the helepoleis 
to be placed in position and to launch missiles directly at the 
fortifications, as well as over them into the fortress. The 
Byzantines kept up the barrage night and day, changing the 
pulling teams at regular intervals. Later, in their turn, the 
Persians encircled Daras, built towers and positioned helepoleis 
around the city (3.11.2). On another occasion, the Avars set up 
helepoleis around Drizipera (6.5.4). In 715, the usurper Theo­
dosios had a difficult time gaining access to the imperial palace, 
even though he had assaulted it for a long time with all sorts of 
helepoleis, £A.E1tOA.EWV £18EO'l 1tUVW101<;.19 

King James I the Conqueror," Iberia and the Mediterranean World of the Middle 
Ages: Essays in Honor of Robert I. Burns, S.J., ed. P. Chevedden, D. J. Kagay, P. 
G. Padilla (Leiden 1996) II 47-94. The Souda (dated to ca 1000) defines 
helepolis simply as a machine used in besieging cities, but elsewhere notes that 
a wall faced with unbaked bricks stands up better against helepoleis than 
does one of baked bricks and stones, which shatter and lose their mortar; the 
soft brick apparently absorbs the shock of the missiles: E 799, A 239 = n 1777 
(II 243, I 27, IV 149 Adler). 

17 Iosephi Genesii Regum libri quattuor 2.2, edd. A. Lesmueller-Werner and 
I. Thurn (CFHB 14: Berlin/New York 1978) 24.22-23. 

18Simocatta 2.18.2-6. Also an Armenian account of Herakleios' siege of 
Tiflis in 624, "four-wheeled balistra and divers other weapons built by 
Roman engineers with which they unerringly hurled enormous boulders to 
breach the walls" : The History of the Caucasian Albanians by Movses 
Dasxuranci, transL C. J. F. Dowsett (London 1961) 85. 

19 Vita of St Germanos, ed. L. Lamza, Patriarch Germanos 1 von Konstanti­
nopel (715-730) (Das ostliche Christentum N.F. 27 [1975]) 200-240, esp. 216. 



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GEORGE T. DENNIS 105 

In 821-823, the forces of the would-be emperor Thomas 
brought up "rams, tortoises, and some helepoleis in order to 
shake down the walls" of Constantinople (Theoph.Cont. 2.13). 

In addition to petroboioi, ladders, rams, tortoises, as well as fire 
arrows from his ships, Thomas ordered the engagement of some 
four-legged helepoleis, ncrl 't£'tpacrK£A£crlv £A£1tOA£crlV (2.14). 

These last were obviously large, trestle-framed, traction trebu­
chets, the other petroboioi perhaps being smaller. "Every day 
large bands of soldiers brought these machines forward against 
the walls of the city" (2.18). 

In their assault on Amorion in 838, the Saracens employed 
"all kinds of machines and helepoleis by which a city is taken 
and plundered," j.lTjxavTj~Hl'tWV Kat £A£7t0 A£CI)V .20 The helepoleis 
were moved forward and "in thirteen days the walls were cast 
down by the operation of the helepoleis" (12.5,65.6-7). 

Siege machines, incidentally, also figure in spiritual warfare. 
The helepoleis of invisible enemies pound the soul, demolish 
virtue, and assault the monk with bolts of improper desires. 21 

Demons fired temptations like missiles at saints such as 
Athanasios of Athos and Gregory of Dekapolis: £A£1tOA1V 'trov 
7tElpacrj.lrov Klvf]crae;, 'tae; 'trov av'tl1t(XAWV £A£1tOAEle;.22 

Constantine Porphyrogennetos compiled an inventory of the 
weapons and equipment assembled for the unsuccessful in­
vasion of Crete in 949 (De caer. 2.45). For attacking a fortress, 

20Skazanija 0 42 amorijskich muamikach, ed. V. Vasil'evskij and P. Nikitin 
(St Petersburg 1905) 11.30. For an Arab account of this siege see P. Chevedden, 
"The Hybrid Trebuchet: The Halfway Step to the Counterweight Trebuchet," 
On the Social Origins of Medieval Institutions. Essays in Honor of Joseph 
O'Callaghan, ed. D. J. Kagay and T. M. Vann (Leiden 1998) 179-222, esp. 189 
[hereafter CHEVEDDEN]. 

21 Eus. HE 10.4.57; Nilus Mon.exerc. 54 (PC 79.7928); Isid. Pel . Ep. 87 (PC 
78.244A). Clearly, these authors were not thinking of trebuchets but of earlier 
kinds of artillery. 

22 Vitae duae antiquae sancti Athanasii Athonitae, ed. J. Noret (Turnhout 
1982) A.114.2-3 (p.54); Ignatius Diakonus und die Vita des hi. Cregorios Deka­
polites, ed. G. Makris (Byzantinisches Archiv 17 [Stuttgart/Leipzig 1997]) 
8.5. 



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106 BYZANTINE HEAVY ARTILLERY 

KCX(j'tpo~cxxicx, 'tEtxo~cxxicx, the ships were to transport large 
arrow-firing ballistae, 'to~o~cxA.i(j'tpcxt IlEYaA.<Xl, and a number of 
1tE'tpCXpECXt. Next in order the manifest listed A.CX~~OCXpEat, some­
times written as A.CXI30CXpECXt; this often designates two-legged 
supports, lambda-shaped, on which a heavy spear rested with 
its point projecting toward the enemy.23 But Constantine lists 
this among the mangana, siege machines, together with petrareai 
and alakatia. There were four petrareai, four lambdareai, and four 
alakatia and, for these twelve engines, there were twelve iron 
slings, in addition to various nuts and bolts. As noted above, in 
the Taktika of Constantine's father Leo, alakatia were clearly 
trebuchets. It seems likely, then, that the petrareai,lambdareai, 
and alakatia were trebuchets constructed according to three 
different patterns. 

Constantine also recommended that the emperor take a num­
ber of books along with him on a military expedition.24 Among 
these were manuals of strategy, mechanical treatises, including 
the construction of helepoleis, the fabrication of missiles, and 
other works helpful in waging war and conducting sieges. 

To commemorate the successful invasion of Crete by Nikeph­
oros Phokas in 961, Theodosios the Deacon composed a poem 
in which he depicted a very large trebuchet hurling a live jackass 
into the enemy city. The commander placed the animal in the 
sling and ordered the men to launch it, II a live jackass for the 
jackasses." The men stationed among the braided ropes then 
sent the unfortunate beast along the skyway.25 Even if the flight 
were only one of poetic fancy, it must have been credible to con­
temporaries that a live ass could actually have been propelled 
skyward by a large trebuchet. 

23E. McGeer, "MEVUUAlOV-MEVUUA.a.tOt," Diptycha 4 (1986) 53-58; "Tra­
dition and Reality in the Taktika of Nikephoros Ouranos," DOP 45 (1991) 
129-140, esp. 134-135; Chevedden 199-200. 

24Three Treatises on Imperial Military Expeditions, ed. J. Haldon (CFHB 28 
[Vienna 1990]) C.197 (p.106). 

25Theodosii diaconi de Creta capta, ed. U. Criscuolo (Leipzig 1979) 716-
721; cf. 326, 973. 



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GEORGE T. DENNIS 107 

The Sylloge Tacticorum, probably compiled about the middle 
of the tenth century, offers suggestions for defending against 
missiles hurled by stone-throwing engines and helepoleis, 1tE'tpO­

~OAOOV opyavoov Kat £AE1tOAEOOV (53.5). The difference between 
the two, if indeed there is one, may be that the helepoleis were 
more powerful. 

Later in the century another military manual recommended 
that an army besieging a city should pitch camp far enough 
away to be out of range of arrows or missiles from the stone­
throwing machines. But it should not be too far from its own 
siege engines, 1tOAWpKllttKa opyava; otherwise, the defenders 
may sally forth and chop them down and burn them.26 The 
attacking troops should encamp close enough so that they can 
race out of their tents to protect their helepoleis, to'i~ EAE-

1tOAtKO'i~ opyaVOt~ (26.20 [p.316)]. The manual again mentions 
1tE'tPO~OAOt Kat £tEpa £AE1tOAtKa and discusses the placement 
of stronger helepoleis, ta KpElnOVa tWV EAE1tOA1KWV 1J-1lXavll­
IJ-atoov, and urges that there be no letup in the bomba.rdment 
(27.2-9, 26.16 [pp.318, 316]). 

In his history of the reigns of Nikephoros Phokas and John 
Tzimiskes, Leo the Deacon employs generic terms in writing 
about siege weapons: 1t£tpo~oAa opyava, a<pll't£piou~ I-lllxaVac;, 

hll~oAa opyava. But on occasion he is more specific and 
records the use of helepoleis to knock down walls. These were 
constructed in situ by carpenters brought along for this purpose, 
or they were transported on campaign in wagons, probably un­
assembled.27 He also notes that they were useless in the hands 
of an inexperienced crew (10.8 [p.171.17-19]). 

Skylitzes also employs generic terms, such as petroboios, but 
he does mention helepoleis, stone-throwing engines, designed to 

26 "Campaign Organization and Tactics" 21.35-90, ed. G. T. Dennis, Three 
Byzantine Military Treatises (CFHB 25 [Washington 1985]) 306. 

27In situ: 1.9 (p .16.15, 21), 2.6 (p .24.13), 4.10 (p .70.8); transported: 8.4 
(p.132.21), 8.5 (p.134.21), 10.8 (p.171.17). 



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108 BYZANTINE HEAVY ARTILLERY 

pound fortifications, for example outside Melitene in 873, at 
Nicaea in 978, and against Thessaloniki in 1040.28 Against 
Mantzikert in 1048-1049 the Turks employed various kinds of 
helepoleis and all sorts of other machines, 1tOlKtA(W; fA£1tOA£crt 

... 1tav'tOtOl~ d8£crl 1l1lxaVllllanov, and one of their officers 
positioned the helepolis on a nearby hill from which they could 
shoot missiles directly into the city (p.462.53). 

An Armenian account of the Seljuq siege of Mantzikert in 
1054 describes a huge trebuchet, originally built for Basil II, 
called a baban, which weighed some 2,000 kilograms and had a 
pulling crew of 400 men and which could fire stones weighing 
up to 200 kilograms.29 Michael Attaleiates apparently refers to 
the same siege, for he describes a trebuchet operated by a large 
number of men which fired an immense stone against which the 
defenders were helpless (46.8). They were saved only when a 
Latin grabbed a container of Greek fire, dashed out through the 
besiegers, and set the machine on fire. He informs us that when 
Romanos IV Diogenes in 1071 was preparing an assault against 
the same city, he had a large number of helepoleis prefabricated, 
EK 1tapacrK£ufl~ Ka'twpyavwll£va~, from huge beams of all sorts 
and transported by no less than a thousand wagons, obviously 
very large trebuchets (151.8-17). An Arab source speaks of one 
huge trebuchet transported in 100 carts pulled by 1,200 men, 
with a composite beam of eight spars and launching stone-shot 
of 96 kilograms.3o 

In the Alexiad, her history of the reign of her father Alexios I 
Komnenos, Anna Komnene makes it abundantly clear that the 
major artillery piece of the Byzantines was the helepolis and 

28Ioannis Skylitzae Synopsis historiarum, ed. 1. Thurn (CFHB 5 [Berlin/ 
New York 1973]) pp.137.40, 323.9, 413.1l. 

29 Aristakes de Lastivert, Reeit des malheurs de la nation armenienne, trans!. 
M. Canard and Haig Berberian (Bibliotheque de Byzantion 5 [Brussels 1973]) 
83-85; English trans!. R. Bedrosian, Aristakes Lastivere' j's History (New York 
1985) 103-105. See Chevedden 187. 

30See Chevedden 188. 



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GEORGE T. DENNIS 109 

that it was a large, stone-throwing trebuchet. She generally uses 
the term in combination, helepoleis and petrobola organa. And 
she distinguishes three kinds of stone throwing machines: 
helepolis, petrobolos, lithobolos, with the first designating a larger 
and more powerful machine, very likely a hybrid trebuchet, 
petrobolos a more readily available machine, probably medium­
sized, and lithobolos a smaller machine, perhaps of the pole­
frame type, operated by one or just a few men. At any rate, the 
lithoboloi were small enough to fit on top of a wall or a wooden 
tower.31 

Anna notes that the Normans constructed helepoleis to 
bombard Byzantine fortifications.32 Without helepoleis, armies 
would find it difficult to capture fortified places, as did the 
Latins and the Bulgarians.33 Forced to retreat, the Byzantines 
burned their helepoleis so that the enemy would not be able to 
use them.34 Alexios employed helepoleis to destroy the walls of 
Kastoria.35 To drive the Arabs away from the coastline he 
positioned helepoleis on ships.36 The Byzantine general Dalas­
senos employed helepoleis on ships to demolish fortifications 
on land. 37 Anna many times records the regular use of helepoleis 
in sieges.38 

To assist the Crusaders in besieging Nicaea in 1096, Alexios 
is said to have prepared all kinds of helepoleis, most of which, 
however, he had constructed in a manner different from the 
standard patterns (ou KC£'tU 'to-o<; 'trov ,.HlxavlKrov 'tP01tou<;) but 

31 An.Komn. 4.1.1 (I 143.18, 144.4),4.4.5 (I 153.5). 

32An.Komn. 3.12.2 (I 139.20), 4.1.1 (I 144.2), 4.4.4 (I 152.11), 4.5.1 (I 
154.12). 

33An.Komn. 10.9.3 (II 221.24),14.1.6 (III 144.28). 
34 An.Komn. 13.5.6 (III 107.4, 8). 

35 An.Komn. 6.1.1 (II 41.15,21) . 

36An.Komn. 6.13.1 (II 79.17). 

37 An.Komn. 7.8.10 (II 116.13). 

3BAn.Komn. 7.3.2 (II 95.2), 7.8.3 (II 111.15), 9.3.3 (II 165.21), 11 .1.3 (III 
8.15), 11.1.6 (III 10.7), 11.11.7 (III 49.27), 13.3.11 (III 98.29), 13.5.4 (UI 106.13). 



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110 BYZANTINE HEAVY ARTILLERY 

according to plans which he himself had devised and which 
everyone marveled at. 39 This passage of his proud daughter, 
which there is no reason to dispute, is echoed by Euthymios 
Zigabenos in his dedication of a dictionary of heresies.4o He 
praises Alexios for his sound judgment regarding military strata­
gems, his instructions on practical matters, and his mechanical 
genius which, many times, proved to be not inferior to that of 
Archimedes or Palamedes. Allowing for a touch of flattery, it is 
clear that Alexios must have had a reputation for mechanical 
inventiveness. Exactly what form this took is uncertain, but it is 
clear from the campaigns of his son and grandson that he or his 
engineers made significant improvements in the design and 
operation of the helepolis. 

The reigns of John Komnenos and Manuel Komnenos (1118-
1180) witnessed a dramatic increase in Byzantine reliance on 
siege warfare and, consequently, on the helepolis or trebuchet. 
The historian of their reigns, Kinnamos, however, employs only 
generic terms, such as petroboios.41 Niketas Choniates is more 
precise, frequently using the exact term, helepolis. Around the 
same time, John Tzetzes in one of his letters complained that a 
demon had assaulted him with a helepolis, which he defines as 
"a stone-throwing engine by which cities are taken."42 Byzantine 
emphasis in this period on siege warfare may have been due to 
the Komnenian strategy of possessing well-fortified cities; it 
may also have been due to advances in the technology of siege 
warfare, particularly in the design and effectiveness of the 

39 An.Komn. 11.2.1 (III 11.2). 

40 Panoplia dogmatica, at PC 130.20; composed at the request of the emperor: 
An.Komn. 15.9.1 (III 223.18-31). The few scholars who have doubted Anna's 
account are effectively refuted by Chevedden (supra n.16). On military develop­
ments during the Komnenian century (1081-1180) see J. Birkenmeier, The 
Development of the Comnenian Army (diss. Catholic University of America 
1998). 

41 Joannis Cinnami Epitome, ed. A. Meineke (Bonn 1836). 
42Ioannis Tzetzae Epistolae, ed. P. A. M. Leone (Leipzig 1972), scholion on 

ep. 95 (p.172.9). 



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GEORGE T. DENNIS 111 

helepolis, culminating in the invention of the counterweight 
trebuchet. 

Choniates records that in 1130 or 1132 John surrounded 
Kastamon with helepoleis and captured itY At Gangra in 1135 
he kept up a constant barrage of missiles aimed at the houses 
within the city (20.31-39). Against the seemingly impregnable 
Anazarba the following year, the Byzantine trebuchets began 
pounding the city walls, but the Armenian defenders returned 
their fire with stones and fiery iron pellets which set the 
Byzantine helepoleis on fire.44 John had new helepoleis built and 
constructed protective brick ramparts around them; his men 
then demolished the walls and forced their way into the city. In 
1142 he took action against some island-dwellers in Lake 
Pousgouse by lashing small boats together and making a 
platform on which he positioned helepoleis (38.6-12). 

Soon after the triumphal entry of John Komnenos into Con­
stantinople late in 1138, after a victorious campaign in the east, 
Nikephoros Basilakes delivered a lengthy oration in his honor. 
Among other things, he recalls a number of successful sieges. 
One must, of course, make due allowance for rhetorical 
exaggeration but, at the same time, one must acknowledge that 
such an oration, pronounced not long after the events it com­
memorated and before men who had taken part in those events, 
is not completely devoid of historical truth. Against 1 arsus an 
intensive bombardment with large stones, "fired as though by 
ten thousand hands," demolished the forward towers and the 
circuit wal1.45 John ordered the helepoleis to be brought forward 

43 Nicetae Choniatae Historia, ed. I. A. van Dieten (CFHB 11 [Berlin 1975]) 
p.18.73-75, hereafter Nik.Chon. One cannot refrain from noting that research 
would be greatly facilitated if modem editions of such sources as Choruates 
and Skylitizes, unreasonably expensive as they are, had been furnished with 
complete indices. On the trebuchets of John Komnenos as recorded in Arabic 
sources, see Chevedden (supra n.16). 

44Nik.Chon. 26.67-82; cJ. Kinnamos 17.16-18.2. 
45Nicephorus Basilaca, Orationes et epistoiae, ed. A. Garzya (Leipzig 

1984) p.57. 



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112 BYZANTINE HEAVY ARTILLERY 

and soon stones fell from the air, with a rushing sound, upon 
the citadel (58.31-.59.1). The orator corroborates Choniates' 
account of the siege of Anazarba (July 1137), at which the 
defenders managed to burn down the Byzantine helepoleis and 
shoot their operators, to which the emperor responded by 
building new helepoleis and protecting them and the men with 
brick walls (60-61). 

Theodore Prodromos composed several poems commemorat­
ing the victorious campaigns of John Komnenos in the 1130s. He 
praises him for choosing not to endanger his troops by engaging 
the enemy in pitched battle in the open, but for choosing to 
break down the enemy's fortifications instead.46 The emperor 
forced the city to surrender without shedding blood; simply 
setting up his powerful siege machines was enough to bring the 
garrison to its knees (3.78). John then surrounded Kastamon 
with machines hurling rocks heavy enough to break up its 
foundations, hurling them like hail (8.60-64). After taking that 
city, he deployed his stone-throwing engines like a veritable wall 
around Gangra (75-79, 120-124). Prodromos imagines the 
emperor picking up a large stone, placing it in the sling, "the 
destroyer of walls," and ordering the operators, "the stone 
shakers," to hit the target. They fired the machine which 
propelled the stone, making a whistling noise and crushing a 
house and its inhabitants (170-185). 

The historian, the orator, and the poet all agree in emphasiz­
ing the terrifying effectiveness of the siege weapons employed 
by the armies of John Komnenos. And their respect for such 
awesome artillery is clearly reflected in contemporary Arab 
chronicles. It is obvious that these were far more powerful than 
the helepoleis that pounded Thessaloniki late in the sixth 
century and even more powerful than those used by John's 
father in the eleventh. While the texts at our disposal preclude 

46Theodoros Prodromos, Historische Gedichte , ed. w. H6randner (Wiener 
byzantinische Studien 11 [Vienna 1974]) 3.68. 



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GEORGE T. DENNIS 113 

certitude, it is difficult not to recognize in these machines the 
fully developed counterweight trebuchet. 

In 1165 four large Byzantine trebuchets launched huge stones 
against the Hungarian city of ZevgminonY Andronikos Kom­
nenos, after personally adjusting the sling, the winch, and the 
beam, (J(pEv80vTlv,a'tpoq>aAov, AUYov, fired stones which hit 
with such violence that they brought down a section of the wall 
between two towers. The last word, AUYoe" can mean a withe, 
willow branch, a tough, flexible branch, or several branches 
bound together and thus can designate the rotating beam of the 
trebuchet which was made of one shaft of wood or of several 
tied together for greater flexibility. The mention of a winch, not 
needed in a traction trebuchet, indicates that this was a counter­
weight one, the first clear reference to such. This is confirmed by 
the statement that by adjusting the three components, An­
dronikos was able to aim the device with great precision. 

At the siege of Nicaea in 1184 the trebuchets employed by 
Andronikos were put out of commission by stones hurled by the 
defenders (Nik.Chon. 282.73-76). Boasting of his skill in taking 
cities, he again set up his helepoleis and carefully adjusted the 
sling, the beam, and the winch, but his efforts were wasted as 
the defenders sallied forth from postern gates and set the 
machines on fire. Not long afterward, however, his boasting was 
justified at Prusa, where his helepoleis repeatedly struck one 
section of the wall until it crumbled (287.35-39). In 1197 a 
master gunner is said to have inflicted heavy casualties on the 
Byzantine troops assaulting the Vlach-held fortress of Prosakos 
after he rotated the beam (Auyoe,) and adjusted the sling (a<pEv-

8OvTl) of the trebuchet (506.29-33). In 1169 helepoleis were em­
ployed by a Byzantine contingent which had joined the Latins 
in an unsuccessful attack on Damietta in Egypt (163.12-16). 

In his account of the Norman assault on Thessaloniki in 
1185, the archbishop of the city Eustathios wrote that the 

47NikChon. 134.79-82; see Chevedden 



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114 BYZANTINE HEAVY ARTILLERY 

attackers on the western side brought up new kinds of 
helepoleis which were difficult to handle because of their large 
size, and so proved ineffective. Perhaps these were counter­
weight trebuchets either poorly constructed or operated by in­
experienced men. To the east, though, the Normans, mostly 
from the fleet, employed more conventional methods, such as 
mining operations and firing small, antipersonnel stone­
throwers, although they did have two larger ones, one of which 
was called "the daughter of the earthquake."48 Because they 
could be accurately aimed, the small stone-throwers caused a 
good deal of damage. But, Eustathios adds, these were like 
rocks thrown by children compared to the stones, as large as a 
man could lift, hurled by "their mother," the huge trebuchet. As 
the stones whizzed through the air and crashed against the 
walls, the commander in the city was heard to remark: "Listen 
to the old lady" (98-99). 

About 1198 the obnoxious careerist Mesopotamites fell out 
of favor and was "expelled from the palace like a well-rounded 
missile propelled by a powerful helepolis" (Nik.Chon. 491.17-

19). 
In 1204 Leon Sgouros, instead of facing up to the Latin 

invaders, turned against his fellow Greeks and planned to take 
the acropolis at Athens by setting up helepoleis to terrify the 
defenders into surrender (605.74). In an effort to dissuade him, 
Michael Choniates, metropolitan of Athens and brother of the 
historian, "with his pastoral sling hurled missiles of divinely 
inspired words ... as though from a helepolis" (606.85). In 1205 

the Bulgarians besieged the Latins who had taken refuge in the 
citadel of Serres and on a hill opposite it constructed a huge 
helepolis which pounded the walls (619.22-34:). Two years later 
they bombarded Adrianople with helepoleis, which brought the 

48Eustazio di Tessalonica, La espugnazione di Tessaionica, ed. S. Kyriakidis, 
trans!' V. Rotolo (Palermo 1961); this Greek edition is reprinted with English 
trans!. by J. Melville-Jones, Eustathios vf Thessaloniki . TIle Capture of 
Thessaloniki (Byzantina Australiensia 8 [Canberra 1988]) 72-75. 



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GEORGE T. DENNIS 115 

walls crashing to earth (636.25-27). When in 1205 the Vlach 
and Cuman allies of the defenders of Adrianople set his 
helepoleis on fire, the Latin emperor Henry cut down the masts 
of ships along the coast and built new ones, sheathing them in 
iron to protect them from being burned (623-624). 

Early in the fourteenth century, the Greek version of the 
Chronicle of Morea called this weapon by its French name: 
trebuchet, 'tPtll1tOu'tae'to.49 Around the end of that century one 
again finds helepolis used for trebuchet in an account of sultan 
Bayezid's siege of Constantinople in 1396-1397.50 And in 1422 
Murad had trebuchets, this time called EA£1ta.A~£t(; (battlement­
taker), prepared to bombard the city with large stones.51 Thirty­
one years later, however, the walls were pummeled by huge 
stones propelled by gun powder from cannons, and the 
helepolis or trebuchet was sent off to the dustbins of history. 

November, 1999 Department of History 
The Catholic University 

of America 
Washington, D. C. 20064 
nauarchos@aol.com 

49To XPOVl1(OV tOll Mope~, ed. P. M. Kalonaros (Athens 1940) 852, 1412,. 
1700, 8430, 9155. 

sop. Gautier, "Un rI?cit inedit du siege de Constantinople par les Turcs 
(1394-1402), " REB 23 (1965) 100-117, at 106.36. 

51Ducas, lstoria Turco-Bizantina (1341-1462), ed. V. Grecu (Bucharest 
1958) 28.6 (p.235.29) .