A Romansiege tower orbreaching tower (or in theMiddle Ages, abelfry[1]) is a specializedsiege engine, constructed to protect assailants and ladders while approaching the defensive walls of afortification. Thetower was often rectangular with four wheels with its height roughly equal to that of the wall or sometimes higher to allowarchers orcrossbowmen to stand on top of the tower and shoot arrows or quarrels into the fortification. Because the towers were wooden and thus flammable, they had to have some non-flammable covering of iron or fresh animal skins.[1]
Evidence for use of siege towers inAncient Egypt andAnatolia dates to theBronze Age. They were used extensively in warfare of the ancientNear East after theLate Bronze Age collapse, and in Egypt byKushites from Sudan who founded the25th dynasty. Duringclassical antiquity they were common amongHellenistic Greek armies of the 4th century BC and laterRoman armies of Europe and the Mediterranean, while also seeing use inancient China during theWarring States Period andHan dynasty. Siege towers were of unwieldy dimensions and, liketrebuchets, were therefore mostly constructed on site of thesiege. Taking considerable time to construct, siege towers were mainly built if the defense of the opposing fortification could not be overcome byladder assault ("escalade"), bymining, or by breaking walls or gates with tools such asbattering rams.
The siege tower sometimes housedspearmen,pikemen, andswordsmen orarchers andcrossbowmen, who shotarrows andquarrels at the defenders. Because of the size of the tower it would often be the first target of large stone catapults, but it had its own projectiles with which to retaliate.[1]
Siege towers were used to get troops over an enemy curtain wall. When a siege tower was near a wall, it would drop agangplank between it and the wall. Troops could then rush onto the walls and into the castle or city. Some siege towers also had battering rams which they used to bash down the defensive walls around a city or acastle gate.
In theFirst Intermediate Period tomb of General Intef atThebes (modernLuxor, Egypt), a mobile siege tower is shown in the battle scenes.[2] In modernHarpoot, Turkey, an artisticallyAkkadian style stone carved relief dated circa 2000 BC was found depicting a siege tower, the earliest known visual depiction fromAnatolia (although siege towers were later described inHittite cuneiform writing).[3]
Siege towers were used by the armies of theNeo-Assyrian Empire in the 9th century BC, underAshurnasirpal 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 andbattering rams.
Centuries after they were employed in Assyria, the use of the siege tower spread throughout theMediterranean. During the siege ofMemphis in the 8th century BC, siege towers were built byKush for the army led byPiye (founder of theNubian25th dynasty), in order to enhance the efficiency ofKushite archers andslingers.[4] After leaving Thebes, Piye's first objective was besiegingAshmunein. Having assembled his army for their lack of success so far, the King then undertook the personal supervision of operations including the erection of a siege tower from which Kushite archers could fire down into the city.[5]
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).[6] Towers were used against both land and naval targets. At the time of Emperor Aggripa, 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.[6][7]
The biggest siege towers of antiquity, such as theHellenistic GreekHelepolis (meaning "The Taker of Cities" inGreek) of thesiege of Rhodes in 305 BC byDemetrius I of Macedon, could be as high as 40 m (130 ft) and as wide as 20 m (66 ft). Such large engines would require arack and pinion to be moved effectively. It was manned by 200 soldiers and was divided into nine stories; the different levels housed various types ofcatapults andballistae. 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 atMasada, Israel built bythe Romans during thesiege 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 Romansiege of Cyzicus during theThird Mithridatic War, for example, towers were used in conjunction with more conventional siege weapons.[8]
One of the oldest references to the mobile siege tower inAncient China was a written dialogue primarily discussingnaval warfare. In the ChineseYuejueshu (Lost Records of theState of Yue) written by the laterHan dynasty author Yuan Kang in the year 52 AD,Wu Zixu (526 BC – 484 BC)purportedly discussed different ship types with KingHelü of Wu (r. 514 BC – 496 BC) while explaining military preparedness. Before labeling the types of warships used, Wu said:
Nowadays in training naval forces we use the tactics of land forces for the best effect. Thus great wing ships correspond to the army's heavy chariots, little wing ships to light chariots, stomach strikers tobattering rams, castle ships to mobile assault towers, and bridge ships to light cavalry.
— [9]
With the collapse of theWestern Roman Empire into independent states, and theEastern Roman Empire on the defensive, the use of siege towers reached its height during the medieval period. Siege towers were used when theAvarslaid siege unsuccessfully toConstantinople in 626, as theChronicon Paschale recounts:
And in the section from thePolyandrion Gate as far as theGate of St Romanus he prepared to station twelve lofty siege towers, which were advanced almost as far as the outworks, and he covered them with hides.
— [10]
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 inmoats with protection from the defenders (thus levelling the ground for the siege towers to be moved to the walls). However, the construction of a slopingtalus at the base of a castle wall (as was common incrusader fortification[11]) could have reduced the effectiveness of this tactic to an extent.
Siege towers also became more elaborate during the medieval period; at thesiege of Kenilworth in 1266, for example, 200archers and 11 catapults operated from a single tower.[1] Even then, the siege lasted almost a year, making it the longest siege in all ofEnglish history. They were not invulnerable either, as during theFall of Constantinople in 1453, Ottoman siege towers were sprayed by the defenders withGreek fire.[10]
Siege towers became vulnerable and obsolete with the development of largecannon. They had only ever existed to get assaulting troops over high walls and towers and large cannons also made high walls obsolete as fortification took a new direction. However, later constructions known asbattery towers took on a similar role in thegunpowder age; like siege-towers, these were built out of wood on-site for mounting siegeartillery. One of these was built by theRussianmilitary engineerIvan Vyrodkov during thesiege of Kazan in 1552 (as part of theRusso-Kazan Wars), and could hold ten large-calibre cannon and fifty lighter cannons.[12] Likely, it was a development of thegulyay-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 theUkrainianCossacks.
During theImjin War, the Japanese utilized siege towers to scale the walls ofJinju but were beaten back several times byKorean cannons.[13][14] In the early 19th century, theJoseon Army utilized siege towers to lay siege to Jeonju where the last ofHong Gyeong-Rae's Rebellion made their stand but were beaten back several times by the rebels.[15]
In modern warfare, some vehicles used bypolice tactical units,counterterrorists, andspecial 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 enteredUngdomshuset inCopenhagen,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.[16]
