St. Gregory Palamas

Gregory Palamas (Greek: Γρηγόριος Παλαμᾶς; c. 1296 – 1357 or 1359[1]) was a Byzantine Greek theologian and Eastern Orthodox cleric of the late Byzantine period. A monk of Mount Athos (modern Greece) and later archbishop of Thessaloniki, he is famous for his defense of hesychast spirituality, the uncreated character of the light of the Transfiguration, and the distinction between God's essence and energies (i.e., the divine will, divine grace, etc.). Source: Wikipedia