born Nov. 11/14, 1296, Constantinople
died 1359, Thessalonica, Byzantine Empire
Eastern Orthodox priest.
From 1332 he was the chief defender of the school of mysticism known as Hesychasm, which integrated repetitive prayer with bodily postures and controlled breathing. His Apology for the Holy Hesychasts (1338) is a justification for mystical experience that involves both soul and body; his Book of Holiness (1344) is the fundamental textbook of Byzantine mysticism. He was made bishop of Thessalonica in 1347, and in 1368 he was acclaimed a saint and named Father and Doctor of the Orthodox church.