Michael VIII succeeded in achieving a union of the Catholic and Orthodox churches at the Second Council of Lyons in 1274, legitimizing him and his successors as rulers of Constantinople in the eyes of the West. Michael's son and successor Andronikos II wished to further legitimize the rule of the Palaiologan dynasty. Other crusader states had been formed in Greece as a result of the Fourth Crusade, notably the Kingdom of Thessalonica, which had been ruled by the Aleramici family of Montferrat. In an effort to rid himself of the threat that an Aleramici pretender might launch an invasion and attempt to seize Thessaloniki in the future, Andronikos married Yolande of Montferrat in 1284, bringing her dynastic claims to Thessaloniki into his own family line. Since Yolande was second-in-line to the throne of the March of Montferrat, the marriage had the unexpected result of creating the possibility that a Byzantine prince might inherit Montferrat. When Yolande's brother, John I of Montferrat, died without children in 1305, Montferrat legitimately passed to Yolande and her children.