Possible motivations for this complete rebuilding by Al-Adil include the damage the old citadel may have sustained from earthquakes in 1200 and 1201 and the threat that other Ayyubid princes continued to pose toward Al-Adil . The most likely motivation is that the defences of the old citadel became obsolete due to the introduction in the 12th century of the counterweight trebuchet , a siege engine easily capable of reducing thick stone walls to rubble . The new citadel introduced a number of important changes to the defensive system , including higher and thicker walls , a wide moat surrounding the citadel , and numerous closely spaced , high , massive towers . Unlike the older towers , these were square rather than round in design . The towers contained platforms on which trebuchets could be placed . Due to their high position , these trebuchets could outrange enemy artillery and thereby prevent them from breaching the walls
earthquakes in 1200 and 1201
1202 Syria earthquake
Citadel of Damascus