The result of the short-lived Roman-Turkish friendship was tension between Byzantium and Persia. During the reigns of Justin, Tiberius, and Maurice an almost continuous war was conducted against the Persians. During the reign of Justin II this was very unsuccessful for Byzantium. The siege of Nisibis was abandoned, the Avars from beyond the Danube invaded the Byzantine provinces in the Balkans, and Daras, an important fortified border town, after a siege of six months passed into the hands of the Persians. This loss so deeply impressed the weak-minded Justin that he became insane, and it was the Empress Sophia who, by paying 45,000 pieces of gold, obtained the respite of a year's truce (574). A Syrian chronicle of the twelfth century, based of course on an earlier source, remarked: On learning that Daras had been captured ... the emperor was in despair. He ordered shops to be closed and commerce to cease.
The Persian war under Tiberius and Maurice was more successful for the Byzantine Empire because Maurice's able leadership was aided by internal dispute in Persia for the throne. Maurice's peace treaty was of great importance; Persarmenia and eastern Mesopotamia, with the city of Daras, were ceded to Byzantium; the humiliating condition of annual tribute was canceled; and finally, the Empire, free of the Persian menace, was able to concentrate its attention on western affairs, especially on the unceasing attacks of the Avars and Slavs in the Balkan peninsula. Another war with Persia began under the reign of Phocas, but the discussion of this war is deferred because, while it was of exceedingly great importance to the Byzantine Empire it was not concluded until the reign of Heraclius