I. Chosroes I Chusro, Cosro,hj Anosharvan “of the immortal soul”. King of the Persians 531–579. After the Mazdakite insurrections under his father Kavadh, Chosroes, appealing to the nobility and clergy, introduced sound reforms to consolidate political power. In the interests of the nobility, he imposed rigid differentiation of social classes, sanctioned by religious authority. An administrative reform based on centralization strengthened royal power; a new tributary organization, in connection with Diocletian’s fiscal reform, served the same end. A new military organization was based on the cavalry, supported in case of necessity by the structures of the state. Mazdakism was suppressed and the Zoroastrian church was restored; at the same time Christianity spread increasingly. A significant Byzantine influence was followed by an Indian one. When Justinian closed the Academy of Athens in 529, its members were welcomed at the court of Ctesiphon. The “perpetual” peace concluded between Chosroes and the Byzantine emperor in 532 was broken in 540 by the Persians, who advanced as far as Syria, reaching the Black Sea via the Caucasus. By paying high tributes, Justinian obtained a truce and finally, in 562, a 50-year peace treaty. II. Chosroes II Aparwez Aparviz 591–628. Nephew of Chosroes I, he may have been a Christian. With Byzantine help he eliminated his rivals in the Persian aristocracy and consolidated his power, which led to exceptional results against Byzantium. In ca. 604 he began his advance on Syria and Egypt; in 616 he conquered the Nile valley, which remained under Persian rule for ten years. More than once the Persian armies reached the outskirts of Constantinople, until in 627 Heraclius annihilated them near Nineveh. Chosroes was then toppled by a palace plot, tried and condemned to death. His execution inaugurated a period of anarchy.