Saint Gregory Palamas was a 14th-century Byzantine monk and theologian, known for his defense of the Hesychast tradition, which emphasizes inner prayer and the experience of God's presence. He served as the Archbishop of Thessalonica and played a crucial role in the theological debates of his time, particularly against the Barlaam of Calabria, who criticized the Hesychasts. Palamas is best known for his teachings on the distinction between God's essence and energies, asserting that while God's essence remains inaccessible, His energies can be experienced by believers. His works significantly influenced Eastern Orthodox spirituality and theology, and he was canonized as a saint in the Orthodox Church.