Dedicated to the military history and civilization of the Eastern Roman Empire (330 to 1453)

"Time in its irresistible and ceaseless flow carries along on its flood all created things and drowns them in the depths of obscurity."

- - - - Princess Anna Comnena (1083–1153) - Byzantine historian

Sunday, December 11, 2016

Byzantine Heavy Artillery

It is better to give than receive

Rule #1 in life: you can find anything on the Internet.

I stumbled on a long 1999 article about Byzantine artillery by George Dennis. The article, summarized below, adds to the Eastern Roman Empire story of warfare.

Like my previously published 1988 article on the Byzantine Infantry Square, we get a better picture of a highly complex Eastern Roman military machine.

This warfare was not the Classic Roman Legion nor was it the simple knights in shining armor of the West mindlessly slashing at each other in battles. The more we get into the details the more we see that Eastern Roman warfare is almost its own stand alone category in military history.


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 . . . “revolving ballistae at both ends.”

I visualized the wagons as mobile fighting platforms with two medium-sized torsion or tension weapons, ballistae, which revolved 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 horizontal. Torsion weapons, such as the ballista, do not revolve; the onager, which pivots from down to up, moves only at one end.
Emperor Maurice

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 terminology. According to Leo, the wagons accompanying the infantry were to carry . . .  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,” . . .

Clearly, these are stone-throwing machines which could also launch incendiary missiles. 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. 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.

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 Byzantine soldier captured by the Avars, taught them how to construct a siege machine for they were ignorant of such machines. And so he prepared the helepolis to shoot missiles. With this fearsome and skillful device the Avars attacked many Byzantine cities, leveling the fortress of Appiareia in 587 and ten years later attacking Thessaloniki, which successfully resisted. Bousas, and other Byzantine artillerymen, therefore, must have learned how to build and operate these weapons some years before 587.

Now we are talking.
This is a serious weapon.

The fear and destruction wrought by these trebuchets, fifty of which were deployed against Thessaloniki, is vividly described in the Miracula S. Demetrii:

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, petrar°ai, to fire back at the Avaro-Slav artillery. Sailors on the ships bringing supplies to the city were said to be experienced operators of these petrareai.

In Byzantine usage, however, helepolis, as will be clear in the following pages, almost invariably means a stone-throwing trebuchet.

This use of helepolis to mean trebuchet is found as far back as . . . the seventh century. . . a Byzantine attack on a Persian fortress situated on a height. 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.

Lord of the Rings Catapult Scene
Ignoring the dragons, the siege of the city of Minas Tirith by the forces of 
Mordor is an impressive recreation of pre-gunpowder warfare. Many have
commented that Tolkien patterened Minas Tirith after Constantinople. 
A shrunken, weakened, outnumbered empire fighting a hopeless fight
for what is left of civilization.

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. In addition to petroboloi, ladders, rams, tortoises, as well as fire arrows from his ships, Thomas ordered the engagement of some four-legged helepoleis. These last were obviously large, trestle-framed, traction trebuchets, the other petroboloi perhaps being smaller. “Every day large bands of soldiers brought these machines forward against the walls of the city”.

Constantine Porphyrogennetos compiled an inventory of the weapons and equipment assembled for the unsuccessful invasion of Crete in 949. For attacking a fortress, the ships were to transport large arrow-firing ballistae. 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.

Constantine also recommended that the emperor take a number of books along with him on a military expedition. 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. 

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 stonethrowing machines. But it should not be too far from its own siege engines, poliorkhtikå ˆrgana; otherwise, the defenders may sally forth and chop them down and burn them. The attacking troops should encamp close enough so that they can race out of their tents to protect their helepoleis.

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. 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. They were saved only when a Latin grabbed a container of Greek fire, dashed out through the besiegers, and set the machine on fire. 

When Romanos IV Diogenes in 1071 was preparing an assault against the same city, he had a large number of helepoleis prefabricated from huge beams of all sorts and transported by no less than a thousand wagons, obviously very large trebuchets. 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.

Reenactment Event at Birdoswald. Men load a Catapulta.

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 that it was a large, stone-throwing trebuchet.

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

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.

In 1130 or 1132 John surrounded Kastamon with helepoleis and captured it.43 At Gangra in 1135 he kept up a constant barrage of missiles aimed at the houses within the city. 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. 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

In 1165 four large Byzantine trebuchets launched huge stones against the Hungarian city of Zevgminon. Andronikos Komnenos, after personally adjusting the sling, the winch, and the beam, fired stones which hit with such violence that they brought down a section of the wall between two towers.

Early in the fourteenth century, the Greek version of the Chronicle of Morea called this weapon by its French name: trebuchet. 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. And in 1422 Murad had trebuchets, this time called (battlementtaker), prepared to bombard the city with large stones. 

Thirtyone 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

(deremilitari.org)      (deremilitari.org - helepolis)