Saint Gregory of Sinai (b. c. 1260)
Gregory of Sinai or in Serbian and Bulgarian Grigorije Sinaita (around 1260s – 27 November 1346) was instrumental in the emergence of hesychasm on Mount Athos in the early 14th century.Born in Smyrna, he was captured by Seljuk Turks as a young man, and eventually ransomed to Cyprus, whence he became a monk at Saint Catherine's Monastery. Later, he moved to Crete, where he learned the practices of hesychasm from a monk named Arsenios, and in 1310 he went to Mount Athos, where he remained until 1335. Increasing Muslim raids on Athos pushed Gregory and some disciples into the Bulgarian Empire, where he would find protection under Bulgarian Emperor Ivan Alexander and where he founded a monastery near Paroria, Strandzha mountains in southeast Bulgaria.

The Philokalia includes five works in Greek by Gregory,

On Commandments and Doctrines, Warnings and Promises; on Thoughts, Passions, and Virtues, and also on Stillness and Prayer: 137 Texts

Further Texts

On the Signs of Grace and Delusion, Written for the Confessor Longinos: Ten Texts

On Stillness: Fifteen Texts

On Prayer: Seven Texts