In the Levant, the Byzantine Emperor John II Comnenus sought to reinforce Byzantine claims to suzerainty over the Crusader States and to assert his rights over Antioch. These rights dated back to the Treaty of Devol of 1108, though Byzantium had not been in a position to enforce them. In 1137 he conquered Tarsus, Adana, and Mopsuestia from the Principality of Armenian Cilicia, and in 1138 Prince Levon I of Armenia and most of his family were brought as captives to Constantinople. This opened the route to the Principality of Antioch, where Raymond of Poitiers, Prince of Antioch, and Joscelin II, Count of Edessa, recognized themselves as vassals of the emperor in 1137. Even Raymond II, the Count of Tripoli, hastened northwards to pay homage to John, repeating the homage that his predecessor had given John's father in 1109.