Acilisene, the ancient city that is now Erzincan, was the site of the Peace of Acilisene by which in AD 387 Armenia was divided into two vassal states, a smaller one dependent on the Byzantine Empire and a larger one dependent on Persia. This is the name (Ἀκιλισηνή in Greek) by which it is called by Strabo in his "Geography", 11.4.14. The etymological origin of the word is disputed, but it is agreed that the city was once called Erez. For a while it was called Justinianopolis in honour of Emperor Justinian. In more recent Greek it has been called as Κελτζηνή ("Keltzene") and Κελεζηνή ("Kelezene")