Saint John of Damascus

John was born in Damascus in the late 7th century, son of Sergius, an official at the Arab caliph's court. He was educated by the monk Cosmas of Sicily together with his adoptive brother, the future hymnographer Cosmas the Melodist, and succeeded his father as an adviser to the caliph. When persecution of Christians broke out, he withdrew to Jerusalem and became a monk at Mar Saba, where he spent the rest of his life writing.

Under Emperor Leo III, during the persecution of icons, John wrote three treatises defending their veneration. According to tradition, the emperor retaliated with a forged letter to the caliph accusing John of treason, and his right hand was cut off as a result; it was miraculously healed after he prayed before an icon of the Theotokos. He died in peace in 749 at Mar Saba, became known as "Chrysorroas" for his eloquence, and wrote the major dogmatic work "The Fountain of Knowledge".