 According to Arab accounts, an Arab prisoner who had converted to Christianity defected back to the caliph, and informed him about a place in the wall which had been badly damaged by heavy rainfall and only hastily and superficially repaired due to the city commander's negligence.As a result, the Arabs concentrated their efforts on this section.The defenders tried to protect the wall by hanging wooden beams to absorb the shock, but they splintered, and after two days a breach was made.