c.1320-1371. Greek theological and mystical writer. He was born in Thessalonica of an aristocratic family, and although his father's name was Chamaetos, he is known by the more famous surname of his mother and his uncle. After an early political career linked with the pretender John VI Cantacuzenus, his public activity waned with the latter's abdication; we know little of his life after 1354, although his friends sought his participation in affairs. It is uncertain whether he was ordained. His best-known works are treatises on Life in Christ and The Exposition of the Divine Liturgy in which he expounds the saving work of Christ mediated through the sacraments, especially the Eucharist, appropriated by the believer steadfast in his adherence.