After receiving the submission of Harran and Edessa, Mongol leader Hulagu Khan crossed the Euphrates, sacked Manbij and placed Aleppo under siege. He was supported by forces of Bohemond VI of Antioch and Hethum I of Armenia. For six days the city was under siege. Assisted by catapults and mangonels, Mongol, Armenian and Frankish forces overran the entire city, except for the citadel which held out until 25 February and was demolished following its capitulation. The ensuing massacre, that lasted six days, was methodical and thorough, in which nearly all Muslims and Jews were killed, though most of the women and children were sold into slavery. Also included in the destruction, was the burning of the Great Mosque of Aleppo.