Venerable Symeon the New Theologian, mystic and hymnographer of the light of God.
March 12
St. Symeon the New Theologian was born in Paphlagonia in 949 and, as a young man in Constantinople, came under the guidance of the elder Symeon the Pious of the Studion monastery. He became abbot of the monastery of St. Mamas, where he taught that every Christian is called to a conscious experience of the grace of the Holy Spirit, and he wrote hymns and discourses of extraordinary boldness on the vision of the divine light.
Opposed by some of the hierarchy, he was exiled across the Bosphorus, where he founded a small monastery and reposed in 1022. He is one of only three saints given the title Theologian by the Church. His memory is kept on March 12 and also on October 12.
October 12
Symeon was born in Paphlagonia around 949 and raised in Constantinople, where as a young man he became the disciple of Symeon the Pious of the Studion. He was made abbot of the monastery of Saint Mamas, which he restored in life and discipline.
His teaching that every Christian may consciously experience the grace of the Holy Spirit as light brought him opposition and exile, but his hymns and discourses earned him the title Theologian, given only to two others. He reposed in 1022.
Feast day
On the New Calendar, Symeon the New Theologian is commemorated on March 12. Churches on the Old (Julian) Calendar keep the feast on March 25 of the civil calendar.
On the New Calendar, Symeon the New Theologian is commemorated on October 12. Churches on the Old (Julian) Calendar keep the feast on October 25 of the civil calendar.
Also commemorated on March 12

Theophanes the Confessor
Venerable, Θεοφάνης
Venerable Theophanes the Chronographer.
Name days: Theofanis, Theophanis, Theophanes
Gregory the Dialogist
Hierarch, Γρηγόριος ο Διάλογος
Saint Gregory the Dialogist, Pope of Rome, to whom the Presanctified Liturgy is ascribed.
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.