 He began his ecclesiastical career at fourteen in the Lavra of St. Sabbas the Sanctified, near Jerusalem, where he quickly gained the notice of his superiors.Theodore, the locum tenens of the Patriarchate of Jerusalem (745–770) made him his Archdeacon, and sent him to the imperial capital of Constantinople as his official representative at the Sixth Ecumenical Council (680–681), which had been called by the Emperor Constantine Pogonatus, to counter the heresy of Monothelitism.Shortly after the Council he was summoned back to Constantinople from Jerusalem and was appointed Archdeacon at the "Great Church" of Hagia Sophia.