Noted in his own time for his wisdom and virtue, he was called Eubolos, meaning “of good counsel.� He was among the first to oppose the heretical writings of Origen. He was bishop in Patara (according to some sources) or Olympia (according to others), then of Tyre in Phoenecia. Under the Emperor Maximinus, he was attacked by the pagans and received the crown of martyrdom in Chalkis in Greece.

For twenty-eight years he lived the ascetical life on Mt Athos as a disciple of St Gregory of Mt Sinai. Later, he founded the monastery of St Mamas, also on Mt Athos. In 1350 he was elected Patriarch of Constantinople. After four years, he resigned the patriarchal throne to return to the Holy Mountain, but was called back to the throne, where he remained until his death in 1363. He wrote the definitive lives of St Gregory the Sinaite and St Theodosius of Trnovo. He was known to St Maximos Kapsokalyvia (the Hut-burner), who foretold his death: On his final journey to Serbia, on which he died, the Patriarch stopped on Mt Athos, where St Maximos saw him and said, “This elder will not see his flock again, because I hear behind him the hymn over the grave, ‘Blessed are those that are undefiled in the way…’�

He was a prominent nobleman and consul in Constantinople. In the City he founded both the Church of St John the Forerunner in 463, and the monastery thereafter called the Studion in honor of him. The Studion monastery nurtured a long line of ascetics, teachers, and martyrs; perhaps the best known is St Theodore the Studite (November 11), the great defender of the holy icons. The monastery was destroyed by the Crusaders in 1204, restored in 1293 by Emperor Andronicus II.