In the face of the Frankish assault, the caliph of Egypt gave one-third of the overlordship of Tyre to Tughtakin of Damascus, who was much closer at hand for the defence. He also encouraged several diversionary raids from Askalon on Jerusalem, but Tyrian appeals for a major naval relief force never bore fruit. Tughtakin sent 700 knights from Damascus who formed the backbone of the resistance: the Tyrians were unwarlike. Gormond the patriarch, with the barons governing Jerusalem in the captivity of Baldwin II, joined the Venetians in surrounding Tyre on February 16. Siege towers and artillery were constructed, considerably improved by the hard work of Havedic, an artillery expert from Antioch, who was paid out of the public treasury. The arrival of Pons of Tripoli to join the siege was a bad blow for the defenders