ANASTASIUS H  . (d . 721), Roman emperor in the East, whose original name was Artemius, was raised to the throne of Constantinople by the voice of the senate and people in A.D . 713, on the deposition of Philippicus, whom he had served in the capacity of secretary . The empire was threatened by the Saracens both by land and sea, and Anastasius sent an army under Leo the Isaurian, afterwards emperor, to defend Syria; 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, with orders not only to resist the approach of the enemy, but to destroy their naval stores . The troops of the Opsikian province, resenting the emperor's strict measures, mutinied, slew the admiral, and proclaimed Theodosius, a person of low extraction, 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 72I he headed a revolt against Leo, who had succeeded Theodosius, and receiving a considerable amount of support, laid siege to Constantinople; but the enterprise failed, and Anastasius, falling into Leo's hands, was put to death by his orders .