Philotheos Kokkinos (Thessaloniki, c. 1300 – Constantinople, 1379) was the Ecumenical Patriarch of Constantinople for two periods from November 1353 to 1354 and 1364 to 1376, and a leader of the Byzantine monastic and religious revival in the 14th century. His numerous theological, liturgical, and canonical works received wide circulation not only in Byzantium but throughout the Slavic Orthodox world. He is commemorated on October 11, and is regarded as a "Protector of Orthodoxy", alongside Saints Photios the Great, Mark Evgenikos, and Gregory Palamas.