King Leo
Raymond-Roupen, Philip's first cousin who had waged the War of the Antiochene Succession with Philip's father for many years, also claimed the throne of Cilicia as the former heir designate of King Leo I. Upon his defeat and imprisonment by Constantine of Baberon, regent on behalf of Leo's daughter Isabella, the Armenians wanted to renew their alliance with Antioch. They requested that Bohemond IV send a husband to their young queen, and Bohemond offered Philip. Since Philip was Bohemond's fourth son, who could not be expected to inherit Antioch, the Armenians accepted. They made the union conditional upon Philip joining the Armenian Apostolic Church, to which Bohemond agreed.