Our father among the saints Gregory Palamas (1296-1359), Archbishop of Thessalonica, was a monk of Mount Athos in Greece (at Vatopedi Monastery and Esphigmenou Monastery), and later became Archbishop of Thessalonica. He was a preeminent theologian and a proponent of hesychastic theology. His feast days in the Church are November 14 and the second Sunday of Great Lent.
He maintained the Orthodox doctrine that it remains impossible to know God in his essence (God in himself), but possible to know God in his energies (to know what God does, and who he is in relation to the creation and to man), as God reveals himself to humanity. In doing so, he made reference to the Cappadocian Fathers and other early Christian writers.
He continually stressed the Biblical vision of the human person as a united whole, both body and soul. Thus, he argued that the physical side of hesychastic prayer was an integral part of the contemplative monastic way, and that the claim by some of the monks of seeing the uncreated light was indeed legitimate. Like St. Simeon the New Theologian, he also laid great stress in his spiritual teaching on the vision of the divine light.