ANASTASIUS II. (d. 721), Roman emperor in the East, whose original name was Artemius, was raised to the throne of Constantinople in A.D. 713, on the deposition of Philippicus, whom he had served in the capacity of secretary. Anastasius sent an army under Leo the Isaurian, afterwards emperor, to defend Syria against the Saracens ; adopted wise and resolute measures for the defence of his capital; attempted to reorganize the discipline of the army; and equipped and despatched to Rhodes a formidable naval force. The troops of the Opsician province, resenting the emperor's strict measures, mutinied, slew the admiral, and proclaimed Theodosius emperor. After a six months' siege, Constantinople was taken by Theodosius; and Anastasius, who had fled to Nicaea, was compelled to submit to the new emperor and, retiring to Thessalonica, became a monk (716). In 721 he headed a revolt against Leo, who had succeeded Theodosius; but, though he besieged Constantinople, the enter prise failed and Anastasius, falling into Leo's hands, was put to death by his orders.