The emperor's siege of Shaizar was unsuccessful, but Shaizar was heavily damaged. After the siege, Usama left Zengi's service and went to Damascus, which was ruled by Mu'in ad-Din Unur, the atabeg of the Burid dynasty. Zengi was determined to conquer Damascus, so Usama and Unur turned to the crusader Kingdom of Jerusalem for help. Usama was sent on a preliminary visit to Jerusalem in 1138, and in 1139 Zengi captured Baalbek in Damascene territory. In 1140, Unur sent Usama back to Jerusalem to conclude a treaty with the crusaders, and both he and Unur visited their new allies numerous times between 1140 and 1143. During these diplomatic missions Usama developed a friendship with members of the Knights Templar whom he considered more civilized than other crusader orders.Philip K Hitti: An Arab-Syrian Gentleman and Warrior in the Period of the Crusades: Memoirs of Usamah Ibn-Munqidh (Kitab Al-Itibar), pp. 161–170. Afterwards, Usama was suspected of being involved in a plot against Unur, and he fled Damascus for Fatimid Cairo in November 1144.Cobb, Usama ibn Munqidh, pp. 26–31.
