In Roman times, it was part of the Roman province of Osrhoene but had declined by the fourth century. Rebuilt by Byzantine Emperor Leo I (r. 457–474 AD) in 466, it was named '''Leontopolis''' (in Greek Λεοντόπολις or "city of Leon") after him, but the name ''Kallinikos'' prevailed. The city played an important role in the Byzantine Empire's relations with Sassanid Persia and the wars fought between the two empires. By treaty, the city was recognized as one of the few official cross-border trading posts between the two empires, along with Nisibis and Artaxata.