St. Gregory of Sinai (1260s-1346) was instrumental in the emergence of “technical” (Athonite) Hesychasm on Mount Athos, Greece, in the early 14th century. Due to Muslim raids on Athos, he sought protection in Bulgaria, where he founded a monastery. The Philokalia includes five texts by Gregory: On Commandments and Doctrines, Warnings and Promises; On Thoughts, Passions and Virtues; On the Signs of Grace and Delusion; On Stillness; and On Prayer.