He entered monastic life when young and became a disciple of St Gregory of Decapolis (Nov. 20). In the days of the iconoclast heresy, he was privileged to be tortured along with his teacher St Gregory and St Joseph the Hymnographer (April 3) for their defense of the holy icons. When Gregory died, John became Abbot of the Decapolite monastery in Constantinople. He reposed in peace around 820; St Joseph buried him near St Gregory's grave.