Venerable John the Disciple of the Venerable Gregory of Decapolis

John came from the Decapolis of Isauria and became a monk as a youth under Gregory of Decapolis, whose humility and obedience he matched. When Emperor Leo V, the Armenian, revived the Iconoclast policy, John came to Constantinople with Gregory and Joseph the Hymnographer, and the three went about the city strengthening the Orthodox.

Joseph was soon captured on his way to Rome and Gregory died there. John stayed in Constantinople and kept up his labours for others. By the time Joseph returned from prison, John had died; Joseph buried him near the tomb of Gregory and later moved the relics of both into the monastery he built. Rostov notes that another John of the same name, of St Chariton's monastery in Palestine, is sometimes confused with him.