Erzurum (or Erzerum, Arzen in antiquity, Karin in ancient Armenian, Theodosiupolis or Theodosiopolis during Byzantine rule) is one of the Provinces of Turkey, in the Eastern Anatolia Region, to the east of the country. It is surrounded by Kars and Agri to the east, Mus and Bingol to the south, Erzincan and Bayburt to the west, Rize and Artvin to the north and Ardahan to the northeast.