Siege tower

thumb|upright=1.2|right|12th century [[siege of Lisbon with siege tower, trebuchets and mantlets.]]

A siege tower or breaching tower (or in the Middle Ages, a belfry) is a specialized siege engine, constructed to protect assailants and ladders while approaching the defensive walls of a fortification. The tower was often rectangular with four wheels with its height roughly equal to that of the wall or sometimes higher to allow archers or crossbowmen to stand on top of the tower and shoot arrows or quarrels into the fortification. While the towers were primarily constructed of wood and thus flammable, their builders typically incorporated whatever non-flammable coverings could be readily procured including iron and/or fresh animal skins. In modern Harpoot, Turkey, an artistically Akkadian style stone carved relief dated circa 2000 BC was found depicting a siege tower, the earliest known visual depiction from Anatolia (siege towers were later described in Hittite cuneiform writing).

thumb|right|[[Neo-Assyrian Empire|Assyrian attack on a town with archers and a wheeled battering ram; Neo-Assyrian relief, North-West Palace of Nimrud (room B, panel 18); 865–860 BC]]

right|thumb|The remains of the [[Roman Empire|Roman siege-ramp at Masada]]

Siege towers were used by the armies of the Neo-Assyrian Empire in the 9th century BC, under Ashurnasirpal II (r. 884 BC – 859 BC). Reliefs from his reign, and subsequent reigns, depict siege towers in use with a number of other siege works, including ramps and battering rams.

thumb|left|Roman siege tower

Centuries after they were employed in Assyria, the use of the siege tower spread throughout the Mediterranean. During the siege of Memphis in the 8th century BC, siege towers were built by Kush for the army led by Piye (founder of the Nubian 25th dynasty), in order to enhance the efficiency of Kushite archers and slingers. After leaving Thebes, Piye's first objective was besieging Ashmunein. He admonished his assembled army for their failures, and took personal command. He had a wooden siege tower erected from which his archers could overlook the city and fire down on the enemy.

During the siege of Syracuse in 413 BC, Athenians erected a siege tower on ship hull. Alexander did the same at Tyre (322 BC) as did Marcellus in Syracuse (214 BC). Towers were used against both land and naval targets. At the time of Julius Caesar, ship towers were built with a lighter, collapsible design that could be stowed flat on the deck when not in use, lowering the center of gravity.

The biggest siege towers of antiquity, such as the Hellenistic Greek Helepolis (meaning "The Taker of Cities" in Greek) of the siege of Rhodes in 305 BC by Demetrius I of Macedon, could be as high as and as wide as . Such large engines would require a rack and pinion to be moved effectively. It was manned by 200 soldiers and was divided into nine stories; the different levels housed various types of catapults and ballistae. Subsequent siege towers down through the centuries often had similar engines.

However, large siege towers could be defeated by the defenders by flooding the ground in front of the wall, creating a moat that caused the tower to get bogged in the mud. The siege of Rhodes illustrates the important point that the larger siege towers needed level ground. Many castles and hill-top towns and forts were virtually invulnerable to siege tower attack simply due to topography. Smaller siege towers might be used on top of siege-mounds, made of earth, rubble and timber mounds in order to overtop a defensive wall. For example, the remains of such a siege-ramp at Masada, Israel built by the Romans during the siege of Masada (72–73 AD) have survived and can still be seen today.

On the other hand, almost all the largest cities were on large rivers, or the coast, and so did have part of their circuit wall vulnerable to these towers. Furthermore, the tower for such a target might be prefabricated elsewhere and brought dismantled to the target city by water. In some rare circumstances, such towers were mounted on ships to assault the coastal wall of a city: at the Roman siege of Cyzicus during the Third Mithridatic War, for example, towers were used in conjunction with more conventional siege weapons.

One of the oldest references to the mobile siege tower in Ancient China was a written dialogue primarily discussing naval warfare. In the Chinese Yuejueshu (Lost Records of the State of Yue) written by the later Han dynasty author Yuan Kang in the year 52 AD, Wu Zixu (526 BC – 484 BC) purportedly discussed different ship types with King Helü of Wu (r. 514 BC – 496 BC) while explaining military preparedness. Before labeling the types of warships used, Wu said:

Medieval and later use

thumb|left|upright|Sketch of a medieval siege tower

thumb|Chinese siege tower

With the collapse of the Western Roman Empire into independent states, and the Eastern Roman Empire on the defensive, the use of siege towers reached its height during the medieval period. Siege towers were used when the Avars laid siege unsuccessfully to Constantinople in 626, as the Chronicon Paschale recounts:

thumb|Medieval English siege tower

At this siege, the attackers also made use mobile armoured shelters known as sows or cats, which were used throughout the medieval period and allowed workers to fill in moats with protection from the defenders (thus levelling the ground for the siege towers to be moved to the walls). However, the construction of a sloping talus at the base of a castle wall (as was common in crusader fortification) could have reduced the effectiveness of this tactic to an extent.

Siege towers also became more elaborate during the medieval period; at the siege of Kenilworth in 1266, for example, 200 archers and 11 catapults operated from a single tower. Likely, it was a development of the gulyay-gorod (that is a mobile fortification assembled on wagons or sleds from prefabricated wall-sized shields with holes for cannons). Later battery towers were often used by the Ukrainian Cossacks.

During the Imjin War, the Japanese utilized siege towers to scale the walls of Jinju but were beaten back several times by Korean cannons. In the early 19th century, the Joseon Army utilized siege towers to lay siege to Jeonju where the last of Hong Gyeong-Rae's Rebellion made their stand but were beaten back several times by the rebels.

Modern parallels

thumb|A vehicle used by [[GIGN featuring a mechanical assault ladder mounted on its roof, essentially a modern version of a siege tower]]

In modern warfare, some vehicles used by police tactical units, counterterrorists, and special forces can be fitted with mechanical assault ladders with ramps. These are essentially modernized siege towers with elements of escalade ladders, and are used to raid a structure through its upper levels. These assault ladders are not as large or as tall as their predecessors, and are typically only capable of reaching roughly the third or fourth floor of a structure.

On 1 March 2007, police officers entered Ungdomshuset in Copenhagen, Denmark using boom cranes in a manner similar to siege towers. The officers were placed in containers that the crane operators raised and placed against the structure's windows, from which the officers then entered.

Medieval and later use

Modern parallels

See also

Footnotes

Bibliography