Chosroes I (or Khosrow I or Khosrau I) (died 579)

Sassanid king of Persia AD 531-79. During the reign of his father, Kavadh I, he crushed a dangerous revolt by the Mazdakites, and came to the throne after having his brothers assassinated. In 540 he broke the peace made in 531 with Justinian I, thus beginning a 20-year war against the Byzantine empire. His domestic reforms included reorganizing the army and civil service, introducing a new and fairer system of taxation, and promoting learning, science, and commerce.

Chosroes undertook many military campaigns during his reign. He invaded Syria, and took the inhabitants of Antioch to found a new city near Ctesiphon called Khosrau-Antioch. In 562, he concluded a peace settlement with the Romans after fighting them first in Lazica (Colchis) and then in Mesopotamia. He conquered Bactria from the Turks and in 570 made Yemen a Persian dependency.