The monograph reconstructs the church-political activities of St. Theoliptus, Metropolitan of Philadelphia, his theological, ascetic social views. St. Theolyptus is presented as the founder and apologist of the Hesychast movement in Byzantium at the beginning of the 14th century, as a constant fighter against the Arsenite schism throughout the entire period of its existence, as a church and political figure who, on a number of issues, predetermined the position of representatives of the Constantinople political elite.