Saint Gregory the Dialogist, Pope of Rome, to whom the Presanctified Liturgy is ascribed.
St. Gregory the Dialogist, or Gregory the Great, was born in Rome in the sixth century of a senatorial family, served as prefect of the city, and then gave up everything to become a monk. Against his will he was made Pope of Rome in 590, and he governed the Church with great pastoral wisdom in a time of plague, famine and invasion.
He is called the Dialogist from his book of Dialogues on the lives of the Italian saints, and Orthodox tradition ascribes to him the Liturgy of the Presanctified Gifts celebrated in Great Lent. He reposed in 604, and his memory is kept on March 12.
Feast day
On the New Calendar, Gregory the Dialogist is commemorated on March 12. Churches on the Old (Julian) Calendar keep the feast on March 25 of the civil calendar.
Also commemorated on March 12

Theophanes the Confessor
Venerable, Θεοφάνης
Venerable Theophanes the Chronographer.
Name days: Theofanis, Theophanis, Theophanes
Symeon the New Theologian
Venerable, Συμεών ο Νέος Θεολόγος
Venerable Symeon the New Theologian, mystic and hymnographer of the light of God.
Aaron the Prophet
Prophet, Ααρών
Holy Prophet Aaron, brother of Moses and first high priest of Israel.
Demetrios of Georgia
Saint, Δημήτριος της Γεωργίας
Righteous King Demetrios the Self-Sacrificing of Georgia.