The Sack of Thessalonica in 1185 by Normans of the Kingdom of Sicily was one of the worst disasters to befall the Byzantine Empire in the 12th century. The city's governor, David Komnenos, had neglected to make sufficient preparations for the siege, and even forbade sallies by the defenders to disrupt the Norman siege works. The Byzantine relief armies failed to coordinate their efforts, and only two forces, under Theodore Choumnos and John Maurozomes, actually came to the city's aid. In the event, the Normans undermined the city's eastern wall, opening a breach through which they entered the city. The conquest degenerated quickly into a full-scale massacre of the city's inhabitants, some 7,000 corpses being found afterwards. The siege is extensively chronicled by the city's archbishop, Eu