The brothers received an excellent education and were particularly involved in philosophy. Striving towards the knowledge of God, they settled in the Lavra of St. Sava. Here St. Theophanes was tonsured, and later became a hieromonk. The holy brothers were famed as advocates of icon veneration. They boldly fulfilled the mission entrusted them by the Patriarch of Jerusalem and went to Constantinople to denounce the iconoclast emperor Leo the Armenian (813-820). Afterwards, they also denounced the iconoclast emperors Michael Balbos (820-829) and Theophilus (829-842).