Notable Fathers of the Later Byzantine Period.

St. Gregory the Dialogist, Pope of Rome († 604).

St. Gregory the Dialogist, commemorated March 12, was Pope of Rome in the 7th Century and was noted for his many literary works, including his Dialogues on the monastic Saints of Italy. To him is ascribed the writing-down of the beautiful Gregorian Chants as well as the Liturgy of the Presanctified Gifts, during which he is specially commemorated.

St. Gregory Palamas, Archbishop of Thessalonica († ca. 1360).

St. Gregory, commemorated on November 14 and the Second Sunday of Great Lent, was a pious Monk of Mt. Athos, and later was elected to the See of Thessalonica as its Bishop. He is noted for his defense of the contemplative life of hesychasm (inner silence), teaching concerning the uncreated Light of Tabor and the Divine Energies of God, through which man can have true communion with God.

St. John of Damascus (Damascene († 776)).

St. John, commemorated December 4, was noted for his Exact Exposition of the Orthodox Faith, a major dogmatic work, as well as his zealous defense of the Holy Icons, for which he suffered the severing of his hand (miraculously restored by the prayers of the Mother of God). He is also noted for his many sermons on Feast Days, as well as numerous hymns, extensively used in Orthodox liturgical services.

St. Mark, Archbishop of Ephesus (15th Cent.).

St. Mark, commemorated January 19, accompanied the Byzantine Emperor to the Council of Florence, and single-handedly defended the Orthodox faith against the Latins. His brilliant defense of Orthodoxy and his letters after the Council were largely responsible for the Orthodox rejection of this false Council.

St. Photius the Great, Patriarch of Constantinople († 891).

St. Photius, commemorated February 6, was a zealous defender of Orthodoxy against the Latin error of the Filioque, for which he suffered much. He wrote on the Procession of the Holy Spirit and was responsible for the commissioning of Sts. Cyril and Methodius for the conversion of the Slavs.

St. Simeon the New Theologian († 1021).

St. Simeon, commemorated March 12 and October 12, was noted as a brilliant spiritual writer, whose works hold a place of honor in the Phllokalia, a major monastic spiritual work. For this reason he endured persecution and also received the veneration of the Orthodox Church which honors him as the New Theologian.