Khosrau I
However, it was under the rule of the Sassanid emperor Khosrau I ( 531-579), known to the Greeks and Romans as "Chosroes", that Gondeshapur became known for medicine and learning. Khosrau I gave refuge to various Greek philosophers and Syriac-speaking Nestorian Christians fleeing religious persecution by the Byzantine empire. The Sassanids had long battled the Romans and Byzantines for control of present-day Iraq and Syria and were naturally disposed to welcome the refugees.