Hierarch Philotheos Kokkinos, Patriarch of Constantinople

IMPORTANT CORRECTION: the stub was originally titled "Philotheus of Antioch," but the sole available image is directly inscribed in Greek "Ο ΑΓΙΟΣ ΦΙΛΟΘΕΟΣ Ο ΚΟΚΚΙΝ[ΟΣ]" — "Saint Philotheos Kokkinos." Thorough checking found no independently attested ancient martyr named "Philotheus of Antioch" in any source; the closest regionally-linked name is St. Theophilus of Antioch (2nd c., apologist, not a martyr) — a different name and a different person. The entry has been fully reworked to match the identity confirmed by the image.

Hierarch Philotheos was born around 1300 in Thessalonica (his birth name is given in some sources as Phocas Kokkinos). He was tonsured a monk at Sinai and later on Mount Athos, where he became abbot of the Great Lavra. He served as Metropolitan of Heraclea in Thrace, and twice occupied the Patriarchal throne of Constantinople — from November 1353 to 1354, and from 1364 to 1376.

One of the foremost Hesychast theologians, a disciple and biographer of St. Gregory Palamas; probable author of the 1351 Tomos that formalized Hesychasm as Orthodox doctrine; he initiated the canonization of St. Gregory Palamas in 1368. A prolific writer of saints' lives, liturgical texts (he revised the order of the Divine Liturgy and the lectionary), hymns, and polemical works. In 1354, at the request of Grand Duke Algirdas of Lithuania, he established a separate Lithuanian metropolitanate, while working to preserve the unity of the Russian metropolitanate under the jurisdiction of Constantinople.

He reposed peacefully in Constantinople in 1379. His feast is kept on October 11/24, together with St. Photius the Great, St. Gregory Palamas, and St. Mark of Ephesus, as well as within the cycle of the 5th Week of Great Lent.