Oliver of Paderborn and his siege engine at Damietta
By Dominic Francis
Nottingham Medieval Studies, Vol.37 (1993)
Introduction: In the hot weeks of August 1218, the soldiers of the German and Frisian contingents involved in the Fifth Crusade laboured hard to build an innovative siege engine. They hoped that this, with God’s intercession, would enable them to capture the chain tower of Damietta. This strong fortress guarded one end of an iron chain that stretched across the Damietta branch of the Nile. Until then, situated as it was on an island, it had prevented the full investiture of the city. Several attempts to capture it had been made from the river already but had failed as no-one had been able to bring scaling-ladders to bear on the walls. In response to this problem Oliver of Paderborn, although too self-effacing to take the credit himself, designed a siege engine that had not been seen before in medieval warfare:
we joined two ships which we bound together sturdily by beams and ropes … We erected four masts and the same number of sail yards, setting up on the summit a strong fortress joined with poles and a network fortification. We covered it with skins about its circumference … and over its top as a defence against Greek fire. Under the fortress was made a ladder, hung by very strong ropes and stretching out thirty cubits beyond the prow.
Although this sounds unwieldy, the resulting opus ligneum as Oliver terms it could be propelled as vessels from the crusader states had oars as well as sails – thus the outside rowers could still function. In addition, steering boards were usually fixed to the side of a ship – a clear advantage in this case. With ships of the time pulling a draught of only three to four feet, the crusaders were able to place the scaling ladder on the tower and, after some ferocious fighting, capture it.