Cardinal Bessarion is best known as the apostle of union between the two historic Churches and the advocate of cultural reintegration of East and West. Much historical investigation has been concerned with his motives when, as a representative of the Eastern Church, he accepted the short-lived Church Union achieved at the Council of Florence in 1438/9 and subsequently immersed himself in western culture. In the latter case, considerably more attention has been given to his humanist endeavours and philosophical interests than to his theological views. The present study examines Bessarion's writings in correlation with the challenges faced and the steps taken from his early life in the East through his subsequent western career, which led him to find in his own Byzantine heritage a solution to the religious differences between East and West. In his synthesis of mystical theology and Neoplatonic philosophy, Bessarion offered an apophatic understanding of God which rose above dogmatic disputation to provide what he considered to be a means for achieving a true and lasting spiritual union.