The Ancient Tug-of-War Daniel Mirsky

The Ancient Tug-of-War: How the Balance between Military Offense and Defense Changed with the Advance of Technology in the Ancient Empires1

Throughout the growth of the ancient empires, military development was one of the driving forces of technological development. Many of the notable achievements of the Roman

Empire can be partially attributed to military motivations, including the road network, artillery developments, and city defenses. In the case of artillery and defensive developments, there was a strong correlation, with any advance in one leading to a counter-advance in the other. In some cases, the same technologies even benefited both sides, such as the early , which were used both by siege forces and tower defenses. However, the balance between offensive and defensive measures was not always fair, with siege artillery innovations swinging the balance wildly.

This analysis will aim to understand how the development of siege artillery, particularly from the early catapults through the , affected the balance between besiegers and the besieged. To understand this development, this paper will outline the state of siege warfare prior to catapults and up until the development of the cannon. To correlate this to defenses, wall developments and styles will be analyzed from the same time period. In particular the walls of

Constantinople, the walls of Athens, and Hadrian’s Wall will be looked at. These walls withstood multiple battles, some with reconstruction and development and some without.

Further, these walls have been thoroughly studied, reducing the chance that the parallels we draw are due to biased information. Finally, to test the hypotheses made on this correlation, we will

1 The title is a little overstating- this paper deals specifically with the Greeks and Roman Empire from the invention of the in the 4th century BC to the later years of Constantinople, around the 14th century AD. The Ancient Tug-of-War Daniel Mirsky use accounts of siege on these areas to understand how this balance affected the dynamics of battle.

Before looking at either the offensive or defensive developments of the time period, it is necessary to set a base case to compare the developments to. In the case of siege equipment, this is covered through the limited availability of prior siege engines, as discussed below. However, for the defensive developments, we first look at the prescribed recommendations by Philo of

Byzantium, who wrote on siege equipment development, particularly the catapult and , and defenses against these developments. In Belopoiika, Philon writes that a defensive wall must be at least 32 feet wide to withstand catapult stones. To ensure catapults would not damage even such a wide wall, Philon also recommended that stone throwers be kept at least 500 feet away from the main walls (Foley, Vernard, and Soedel). A typical bow-catapult of this period would have a maximum range of around 650 feet, so enemies 500 feet away would be unlikely to do much damage. Philon also includes recommendations on the minimum stone-thrower size necessary to protect against enemy stone throwers. Since Belopoiika was written within a hundred years of the original introduction of the bow-catapults, these recommendations show that defensive considerations for these technologies were quick and important. For example,

Philon recommends 10 and 30 pound shot catapults for the defense against stone-throwing catapults and siege towers, respectively (Ober).

In order to understand the context of the walls and sieges discussed hereafter, the development of siege warfare, particularly the catapult, , and related siege engines2, must first be understood. This subject has been discussed at great length and it would not add to

2 There are nomenclature issues related to the ancient siege engines. In this paper, catapult refers to the torsion- powered, arrow firing . Ballista refers to the stone-throwing equivalent and refers to the vertical- armed equivalent. Bow-catapult refers to the gastraphetes (belly-shooter) and related (handheld and not handheld) bow-powered catapults. The Ancient Tug-of-War Daniel Mirsky the contribution of this paper to repeat that discussion here. Rather, the importance of mentioning this development is to agree on the approximate dates of introduction of the relevant devices.

Since the relevance of these dates is dependent on the rate at which the knowledge spread to the cities we discuss, and this is not the topic of this paper, the dates will be used with a relatively low accuracy. This further reduces the necessity of confirming the validity of these dates to the specified accuracy – the analysis will be done on the scale of centuries, not years, and we can safely assume that the researched dates are accurate to the century.

Prior to the development of these siege engines, there were three main siege “machines”: the tortoise, the scaling machine, and mines. The first of these, also known as the battering ram, was used to bring down city walls and towers. In the first uses, the soldiers held a beam in their hands, swinging it back and forth. To make it easier to use, the soldiers suspended the beam from a pole, swinging it back and forth like a pendulum. To make the battering ram mobile, the beam was then mounted on a frame with wheels and covered with a roof to secure the soldiers from danger. The scaling machine was a ladder designed to allow soldiers to climb onto the enemy walls. Finally, tunneling or mining under the walls was very common. The besiegers would erect a wall to cover their plans and start digging a tunnel towards the wall. While digging, the tunnel would be reinforced with timber to keep it from collapsing. Once the besiegers had successfully tunneled under the wall, they could either enter the city or burn the tunnel supports and attempt to collapse a section of the wall. Overall, these and the other common siege tactics of that era were largely ineffective, making the chance of a successful siege very low and giving the advantage to the defenders (Lahanas).

The first big change in siege tactics came about with the creation of more advanced projectile siege engines. The catapult-related siege engines were developed over the course of The Ancient Tug-of-War Daniel Mirsky almost a millennium. The first devices in this class were the gastraphetes, bow-powered, handheld weapons. Heron of Alexandria attributes the invention to Zopyros of Tarentum in the mid-4th century BC, but the weapon likely existed even earlier, as the torsion catapult, described later, was already in use at this time. Originally, these were similar to the conventional archery bows, but were modified with a slide, groove, and hook. An archer would hook the bowstring to the back end of the slider, secure the end of the device against the ground or floor, and press his belly into it. The locking action would keep the tension on the bow as the archer aimed and fired, resulting in significantly more applied power while maintaining considerable ease of aim

(Hacker). Mounted versions of the gastraphetes followed quickly, using levers and other commons tricks to simplify the cocking mechanism and increase tension in the bow. Such mounted versions could be used in towers, giving defenders range equal or greater than that of the attackers. Bow-catapults were able to shoot 650 to 1000 feet, but only with small bolts or standard sized arrows (Ober).

The range and power of siege engines increased dramatically with the invention of torsion powered siege engines. The catapult, also known as the euthytonon, was a torsion powered equivalent of the gastraphetes. Rods were inserted into tensioned sinews or hairs and then attached to a slide. When the catapult was armed, the rods were pulled back, applying further tension to the sinews or hairs and storing an unprecedented level of energy. When fired, the rods sprung back to place with the tension of the sinews and shot the arrow forward. Such a device was still small enough that it could be brought to battle or mounted in a tower without too much trouble, but yet could shoot a 35-inch arrow 1200 feet. The term catapult comes from the

Greek katapeltes meaning shield-piercing, which the catapult was able to do. Two other torsion- powered devices were commonly used – the ballista and the onager, with the ballista operating The Ancient Tug-of-War Daniel Mirsky on the same principle as the catapult, only throwing stones, and the onager operating similarly, only with a vertical arm instead of a slide. The ballista could throw a 1-pound stone almost 1000 feet; the onager could throw 4 pounds the same distance (Hacker, 45). Heavy-weight torsion catapults were later developed that could throw up to 60 pounds, but the range was decreased to under 450 feet (Chevedden et al.). Looking at the absolute maximum ranges, a catapult could fire a standard arrow of about 28 inches a distance of 2000 feet compared to 1500 for an archer

(Foley, Vernard, and Soedel). Unfortunately, these last numbers seem very extreme, as typical archers should shoot less than the bow-catapult, so typical range is likely under 650 feet.

Trebuchets were the final important siege engine before the invention of the cannon.

Trebuchets incorporated an entirely new design, using a large beam on an axle, making the beam into a common lever. The shorter end of the beam had pulling ropes attached, while the longer end had the . When the shorter end was pulled with ropes, typically by hundreds of men, possibly with the help of gravity, the longer end launched the load high into the air. A Chinese traction trebuchet was recorded as firing a 130 pound shot approximately 250 feet with a 250 man pulling crew. The traction trebuchet was introduced to Europe in the 7th century from the

Chinese, who invented it BC (Chevedden et al.). The counterweight trebuchet, a similar device which harnessed the power of gravity instead of a pulling crew was first referenced in the 12th or

13th century. This trebuchet was capable of much higher loads, with loads of 650 pounds typical and reports of over 2200 pounds existing. At low loads, such as 220 pounds, the counterweight trebuchet could achieve a distance of 900 feet. Such a powerful weapon led to “an increase in the scale of warfare and produced revolutionary changes in military architecture.” (Chevedden, 76)

The described development of siege engines did not include many of the problems with each of the devices that helped motivate the innovation of the new engines. For example, the The Ancient Tug-of-War Daniel Mirsky onanger was also known as the “wild ass” because of the violent nature of recoil upon firing.

Because of their immense power, the torsion engines were regarded as extremely dangerous, with accidents or misfires leading to the death of entire crews. However, since this will not be relevant in the analysis of defenses, such information can safely be left to the many other articles on the topic.

The Walls of Athens The first defensive walls of Athens were constructed as early as the 5th century BC, considerably before the catapults were invented in this region of the world. While there may have been archaic walls prior to this time period, they are not important to our discussion. The walls were rebuilt and improved for over a thousand years consisting of four courses and fifteen construction phases. These phases were caused by changing needs of the city and attacks on the city, with attacks constituting the reason for the more extensive rebuilding projects. We shall look at these phases and the development of the wall to get any idea of defensive structure of the time period (Theocharaki).

The first phase of the construction of the wall began during the Themistoklean Period in

479 BC. This phase consisted of construction of a stone base roughly 8.2 to 9.8 feet and a sun- dried mud brick superstructure. In this phase, the base was made up of two stone faces (shown in

Figure 1) with the void between filled with rubble and stone chips. Since this section of the wall reused materials from previous structures, it is no surprise that the core was filled with rubble and not stone. Even some of the blocks used for this phase were reused. In fact, the stone base of the wall was only one or two courses high, with the rest being the mud superstructure. During this phase, sections of the wall also had a moat exterior to the city which was built around the same time as the wall itself (Theocharaki). The Ancient Tug-of-War Daniel Mirsky

Figure 1: Picture of the remains of the base of two stone faces

The next significant change in the construction of the wall came during the sixth and seventh phase, taking place around 330 to 300 BC. The sixth phase was part of a massive reconstruction following the battle of Chaironeia as part of a time of military preparation. During this phase, legal stipulations indicate the project may have been undertaken in order to counter recently invented siege weapons, particularly those of the Macedonians. For the seventh phase, we have clear evidence of the use of recently invented siege engines, as Demochares was honored for “the building of the walls and the preparation of armour, missiles, and engines of war.” Further, decrees for the heavily damaged parts of the wall required “for those sections that are to be constructed from their foundations unworked stones should be placed.” Parts, if not all, of the wall reconstructed during this phase were all-stone, showing a clear trend towards more The Ancient Tug-of-War Daniel Mirsky careful material selection. For the more vulnerable parts of the wall, an estimated height of over

30 feet was specified (Theocharaki).

The later phases of the wall follow a similar trend, with a general widening of the base and increase in the height of the walls. Construction was also more commonly all-stone, but two- faced stone walls were also used due to demands of the terrain. The walls were able to withstand various siege attempts, even leading to some surprise of their strength. During the invasion of the

Roman general Sulla in the early first century, these characteristics helped provide an initial defense for the Athenians, although Sulla was able to break through one section of the wall after leveling the ground. The state of the wall was questionable for some period after, with the next major reconstruction occurring after 200 AD. Later reconstructions were all stone, with Justinian repairs also filling in the void between the two stone faces. During the Justinian era (ca. 5th century AD), a significant number of towers were added, halving the original distance between the towers to just under 130 feet. Parts of the reconstructed base were also wider, with the new maximum being about 16.4 feet (Theocharaki).

Although we do not have conclusive evidence on the exact height of the wall, the largest surviving sections are about 15 feet high. Since important sections were specified as 30 feet high, it is very likely that the original height was well over 20 feet, but likely under 30 feet for most of the wall. During the Justinian era, increasing the height of the towers was a concern, but no data no height is given, unfortunately. However, excavations were able to conclude the distance to the moat usual ranged from 26 to 33 feet, with the moat having a width of up to 41 feet

By looking at the sieges of Athens, we can draw some parallels between the reconstructions of the walls and the relative difficulty or ease of the besiegers in conquering the The Ancient Tug-of-War Daniel Mirsky city. One of these in particular, the siege of Athens by the Roman general Sulla provides evidence of the effect of the wall on the city’s safety. Although Athens was not able to hold off the general, the wall did provide an initial defense. Further, the wall prior to this period had been designed to protect against battering rams, as mud brick construction was better at absorbing the shock from the ram. With a stone wall, a ram would take down the entire height of the wall through a single point of attack. On the other hand, a battering ram would simply create holes in the wall, but the collapse would not be immediate. Based on the development of the weaponry,

Sulla would have likely access to siege engines such as the catapult. However, based off the terrain surrounding Athens, there was little chance for enemy siege engines to attack the wall, likely explaining Sulla’s initial difficulty in besieging Athens (Winter). With this in mind, the walls of Athens should have provided more than enough defenses to protect from siege, yet they were unable to hold off the enemy for long. While part of this may be attributed to Sulla’s ability to cut off Athens food supply, it shows that the balance between offense and defense was not as simple as comparing the siege technology to the wall defenses, especially since the defenders did have the advantage of being able to use projectile siege engines for defense.

The Hadrian Wall The Hadrian wall provides a look at an entirely different type of wall, one that was set up to protect and separate the Roman Empire from non-Roman Britannia. The Hadrian wall stretched over 75 Roman miles from sea to sea, entirely separating the two regions. The wall was built around 122 AD, with the final version having a height of twelve feet and a width of eight feet (Fields, 9). The original construction of the Hadrian wall was described as “a wall, eighty miles long, to separate the Romans from the barbarians” (Breeze, David, and Dobson, 1). The Ancient Tug-of-War Daniel Mirsky

The Hadrian wall was built to secure the northern border of the Roman Empire. Due to conflict at the beginning of Hadrian’s reign with northern Britain, the construction of the wall was started quickly after a visit of Hadrian. Although the revolt was suppressed, the Romans suffered heavy casualties and the need for frontier defense was apparent (Fields, 11).

As an expert on frontier defense, Hadrian ordered the construction of 4 elements to aid in the defense of the wall. On the outside of the wall, a large ditch was dug, up to 40 feet wide.

Outside of the ditch, land from the ditch was piled up to form a large mound (glacis), making any enemy forces stand out against the horizon without offering any cover. The wall itself was typically at least 20 feet away from the ditch partially to prevent wall collapse. Inside of the wall, a Vallum was added during the construction of the wall, likely to prevent any conflict from within the wall. The Vallum consisted of a more gradually sloped ditch almost 20 feet wide at the top and about 40 feet away from the wall (Fields).

To protect the wall from oncoming attacks, a series of forts, turrets, and walkways were constructed. The forts housed the Roman soldiers, spaced so that the distance between them could be marched in about a day. Along the wall, milecastles were placed every Roman mile allowing the crossing of the wall easily. These milecastles were overlooked by turrets, with two between each milecastle, reaching a height of about 31 feet. In order to further facilitate defense of the wall, the top of the curtain-wall had a walk way for troops, allowing javelins and spears to be used to ward off oncoming attackers, as depicted in Figure 2 (Fields, 37). The Ancient Tug-of-War Daniel Mirsky

Figure 2: Trajan's Column depicting a typical siege defense before siege engines

Hadrian’s wall was attacked multiple times from the North. Since it was on the border with “barbarians”, it was not likely to be attacked by catapults and other heavy siege equipment.

Regardless, it was overrun at least twice around the end of the 3rd century or start of the 2nd century. This should come as a surprise, as the wall was remarkably strong, even considered too be exaggerated for its purposes. Further, the lack of siege equipment should give the defenders a significant advantage; as depicted on Trajan’s Column, the defenders should have been able to knock any potential attackers off the wall without too much trouble. There was no chance that the attackers would be able to cut off Roman supplies since the whole empire was on the Roman side of the wall. It seems that the attackers were able to overcome the Roman forces simply The Ancient Tug-of-War Daniel Mirsky because the Romans were spread out too thin and did not have enough soldiers to cover the walls

(Breeze, David, and Dobson). While it may also have been the case that the wall was not overrun and the noted destruction was due to the Romans, it seems unlikely that exposed sections of wall would not be attacked by “barbarians” who had previously overrun Roman forces. Further, it does not make sense that the Romans would build such a wall to protect their forces in an area where heavy losses were previously sustained and then leave the front exposed or forts ungarrisoned.

Even if we ignore evidence of sieges, Hadrian’s wall did have some notable differences from the other walls analyzed. Although the wall was constructed in the 2nd century AD, it did not have the siege defenses in place that would be expected of that era. While this could be attributed to lack of knowledge of the enemy, it also shows that the development of siege weaponry did not spread instantaneously, with no evidence of the attackers using the heavy siege weaponry.

The Walls of Constantinople Due to Constantinople’s “disadvantageous” location, the walls were regarded as an utmost importance. With no mountain protection, the “land it is most disadvantageous in both respects,” as written by Polybius in the 2nd century BC. When Constantinople was settled in the

4th century by Constantine the Great, he walked around the limits of the city and traced the location of the to-be-constructed walls with his spear. However, Constantinople quickly outgrew these limits and new walls were built in 423 AD. These new walls were known as the

Theodosian Walls and one-third of the land tax of Constantinople went toward the construction of the walls (Turnbull, Stephen, and Dennis). The Ancient Tug-of-War Daniel Mirsky

Unfortunately, the Theodosian Walls did not last long without damage, as a large earthquake in 447 AD destroyed the majority of the walls and 57 towers. With Attila the Hun advancing on Constantinople, the people of the city managed to rebuild the city walls in less than three months. The walls were even strengthened, with 192 towers and another wall built outside of the main walls with a deep moat dug in front of it (Turnbull, Stephen, and Dennis).

The new, heavily strengthened, walls were of enormous proportions. The inner wall was

40 feet high on the side of the city and 30 feet high on the outside. It ranged from 13-15 feet thick, with a 50 to 60 foot gap, known as the peribolos, between the inner and outer wall. The outer wall was smaller, meant as a supplementary defense, ranging from 2 to 6 feet thick and having a height of 10 feet from the side of the peribolos, 27 feet from the outside. After this, a 60 foot terrace extended the distance to the enemy, after which a 60 foot moat prevented their approach. The inner wall also included at least 96 towers reaching up to 30 feet high with a spacing of less than 200 feet. Although not as large, the outer wall towers had a height of up to

35 feet, alternating between the inner towers (Turnbull, Stephen, and Dennis).

Another addition to the walls came in 627 AD, when the Avars attacked Constantinople and ravaged a holy quarter outside of the city walls, Blachernae. These walls had a different construction and were significantly more complex. As this area grew in importance, the wall was further strengthened in 813 AD when the Bulgarians threatened to attack (Turnbull, Stephen, and

Dennis).

Of the walls analyzed and cities discussed, Constantinople had the strongest defenses of the time period. Commonly, this would be attributed to the extremely thorough defensive walls of Constantinople. However, there are many more details to consider. First of all, Constantinople The Ancient Tug-of-War Daniel Mirsky had access to the same siege engines as the attackers. Even counterweight trebuchets, the invention which was said to give attackers an enormous advantage, was expected to play a part in Constantinople’s defenses after the crusades (Turnbull, Stephen, and Dennis). Although the evidence for and against the trebuchet and other large scale siege engines as an advantage for the defense is mixed, there is reason to believe it would be easier to set up defensive siege engines inside of the city, where materials were plenty and some of the smaller engines could be made to pivot. Even though it was suggested that a sieging army could set up a siege engine to fire at a point during the day and continuously bombard that same spot at night, the defenders had the advantage of already being set up and ready to aim while the attackers would still be putting together and moving the siege engines. Finally, since the defenders could install artillery permanently, they would not have the resource limitation of the attackers, who often had to find resources to build siege engines on the spot.

The walls of Constantinople were known to be some of the best during the time period, but still did not fully satisfy Philon’s defense recommendations from the 3rd century BC. First of all, the inner walls were only about 15 feet thick, considerably less than the 32 feet recommended by Philon. To make matters even worse, Philon’s advice was provided during the era of bow-catapults, which did not have that great a range improvement over archers. Torsion catapults and trebuchets, on the other hand, had huge improvements in range and load, likely increasing the minimum wall thickness recommendation even further. The distance to the enemy is also not even close to the 500 feet minimum recommendation, adding up to a total of less than

250 feet from the inner wall to the end of the moat. While the enemy could be kept at the minimum recommended distance, this would require the use of either heavy artillery or foot soldiers outside of the walls. If heavy artillery is available to the defense, as was the case in The Ancient Tug-of-War Daniel Mirsky

Constantinople, the offense will not have the enormous advantage implied by the introduction of the heavy artillery. If this artillery is not available, having foot soldiers ouside of the walls would be the only option, but this would be nearly impossible in the sieges of Constantinople further described.

The siege of Constantinople by the Avars and Persians in 628 AD provides a well- documented example of the balance between the besiegers and besieged. The Avars possessed traction trebuchets, the most up-to-date siege engines of the time. They had multiple types of other siege equipment and had covered the engines in hides to prevent the Constantinople soldiers from setting fire to them. The Chronkon Paschale provides a description of the event

And again on the following day [the leader of the Avars] stationed a multitude of

siege engines close to each other against that part which had been attacked by

him, so that those in the city were compelled to station very many siege engines

inside the wall. When the infantry battle was joined each day, through the efficacy

of God, as a result of their superiority our men kept off the enemy at a distance.

But he bound together his stone-throwers and covered them outside with hides;

and in the section from the Polyandrion gate as far as the gate of St Romanus he

prepared to station 12 lofty siege towers, which were advanced almost as far as

the outworks, and he covered them with hides.

As evidence by this quote, both sides had access to heavy siege equipment, negating the advantage for either side. In the end, even though the Avars had the more recent siege equipment and the help of the Persians, they could not besiege the city, setting fire to their siege engines and turning away disappointed (Turnbull, Stephen, and Dennis). The Ancient Tug-of-War Daniel Mirsky

Conclusion This paper aimed to answer two main questions: How did offense and defense respond to technological development and how did the balance of power between the attackers and defenders change with this development?

We have shown clear evidence that defensive walls responded to the development of siege engines. In particular, the development of the wall of Athens was viewed from the early 4th century BC to the late 3rd century AD, showing a general thickening of the walls and a move towards all-stone construction. Although Athens was not besieged by heavy artillery, the gastraphetes and other small bow-catapults would still likely have been a risk and necessitated the all-stone construction. Further, there is a strong possibility that Athens had siege artillery of its own, mounted on top of the wall or towers as defense against enemy forces. Unfortunately,

Athens fell often and violently, leading to multiple instances of large-scale ravaging of the city.

This, however, stimulated the development and reconstruction of the walls of Athens, keeping them up to modern standards. In particular, the reconstruction of Athens during the Justinian era showed an increase in the number of towers and, as a corollary, a decrease in the spacing between them. This was important for defense against the new style of warfare, as siege engines and, especially, siege towers allowed attackers to get closer to the wall and exploit and possible vulnerabilities. The story of Athens also answers our next question, as the development of siege engines should have benefitted Athens, as its enemies could not utilize large siege engines against Athens for most of the wall. This was not the case, with Athens falling repeatedly, showing that the balance of power was due much more to the skill of the army than the development of the defensive walls. The Ancient Tug-of-War Daniel Mirsky

Hadrian’s wall showed the importance of considering the spread of technology as a factor in the balance of power. Hadrian’s wall was only 8 feet wide, not anywhere close to the dimensions prescribed by Philon for defense against siege engines. Since the “barbarians” didn’t have siege engines, they should have been at a huge disadvantage, yet they were able to overtake the wall, showing that there was more to the balance than just possession of siege equipment. It also showed that the development of the technology alone was not enough evidence to ensure that an attacker had used it in battle, as shown in the case of the walls of Constantinople.

Since Constantinople was considered one of the most defended cities of the Byzantine

Empire, the evidence available was very clear. Constantinople was at a disadvantaged land location since there were no mountains to prevent enemy siege engines. When Constantinople was attacked during the First Crusades, even though many siege engines were already developed, the attackers did not utilize any technology, depending exclusively on their sheer number for attack. The attack failed miserably, showing that just because a technology exists does not mean that attackers will use it. Further, during the siege of Constantinople by the Avars, even though the Avars had a significant technological advantage and the Persians as allies, Constantinople did not fall due to the strong army and the religious backing.

Overall, although we have shown that siege technology did drive wall defenses, it only gave an advantage as much as any other technology which is applicable to both sides; whichever side gets the technology first has the advantage. Once both sides implement the technology, in this case siege engines, the advantages equalize and the balance is restored.

The Ancient Tug-of-War Daniel Mirsky

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Primary:

Trajan’s Column image from

Athens Wall Picture from

Quote from Chronkon Paschale from

Philon recommendations – I didn’t have a direct translation, so I took the two statements from !! and considered them as a translation. Hopefully this is ok.