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 catapults, 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 trebuchets, 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 catapult 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 ballista, 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, trebuchet, 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 siege engine. Ballista refers to the stone-throwing equivalent and onager 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 sling. 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.