The eighty-fifth patriarch of the See of Saint Mark (1363-1369). The biography of John X occupies only three lines in the HISTORY OF THE PATRIARCHS. He is described as Father Yuhanna al-Mu’taman al-Shami, which seems to denote his Syrian origin. He was a man of learning and great virtue. We know nothing of his monastic life or his affiliation with one of the recognized Coptic monasteries.
He is known to have acceded to the throne of Saint Mark during the reign of the Bahri Mamluk sultan, al-Ashraf Sha‘ban (1363-1377), and we must assume that his patriarchate was a peaceful one with no outstanding events connected with his life.