ISAURIAN DYNASTY. The dynasty of emperors who ruled Byzantium (q.v.) from Leo III through Constantine VI (i.e., 717–802). Soldier emperors from the border regions, these rulers came to power in the life or death crisis of the Empire’s confrontation with the tidal advance of Islam (q.v.) under the early Caliphate of Damascus. The advance was halted at the borders of Asia Minor, though not before Constantinople (qq.v.) itself had suffered siege on two occasions, most seriously in 717. The dynasty is perhaps better known for having initiated the Iconoclast Controversy, which sought to advance the role of the emperor in the Church’s life-more than a theological dispute over the place of icons (q.v.). (Leo III wrote of himself as high priest and successor of St. Peter.) The failure of the Isaurian Dynasty in the long run to make good on either its doctrinal program or its vision of the imperial office marked the high-water point of Byzantine caesaropapism (q.v.).