John II Komnenos
Joscelin II ruled the weakest and most isolated of the Crusader states. In 1138 he allied with Antioch and Byzantine emperor John II Komnenos to attack Zengi, atabeg of Aleppo, and the campaign ended with the unsuccessful Siege of Shaizar of 1138. Upon returning to Antioch, Joscelin II exploited local sentiment against the Byzantine Empire to instigate a riot that forced John to return home.