He was originally from Samanoud a city in the North of Egypt, hence also known as Pope John III of Samanoud.
During his papacy the Muslim ruler in Damascus was Marwan I as after the death of Yazid, the son of Mu'âwiyah and his son Muawiya II, Marwan I took control of the East and of Egypt.
And when Abd al-Aziz became governor of Egypt, Pope John III wrote from Alexandria to Misr to the two scribes who presided over his divan, to make known to them what had been done concerning the seal, which was set upon all the places, and the trouble with the Chalcedonians from which he was suffering. Thereupon the said scribes sent messengers to Alexandria with instructions that the seal should be broken in the places named, and that all the property of the Church should be delivered to the Father Patriarch.