Gregory Palamas was a 14th-century Byzantine monk and theologian, best known for his defense of the mystical experience of God. He served as the Archbishop of Thessalonica and is recognized for his teachings on the distinction between God's essence and energies, which became a significant aspect of Eastern Orthodox Christianity. Palamas' ideas were central to the Hesychast movement, which emphasized inner prayer and contemplation. His works, particularly the "Triads," argued that believers could experience God's divine energies through prayer and ascetic practices, contributing to the development of Orthodox spirituality and theology.