Dioceses of the Church of the East to 1318 to represent them. None of these four dioceses is mentioned again, and it is not clear when they lapsed. By the end of the 5th century there were at least three East Syriac dioceses in the Sassanian province of Media in western Iran. Canon XXI of the synod of Isaac in 410 foreshadowed the extension of the metropolitan principle to the bishops of Beth Madaye and other relatively remote regions. Hamadan (ancient Ecbatana) was the chief city of Media, and the Syriac name Beth Madaye (Media) was regularly used to refer to the East Syriac diocese of Hamadan as well
Dvin (ancient city) produced an abundance of materials, which have shed light into the Armenian culture of the 5th to the 13th centuries. Ancient Armenian literary sources almost always give the name of the ancient city of Dvin as "Dwin" or "Duin". Later authors favored the Dvin appellation, which is the most common form given in scholarly literature. The word is of Middle Iranian origin, and means hill. The ancient city of Dvin was built by Khosrov III Kotak in 335 on a site of an ancient settlement and fortress from the 3rd millennium BC. Since then, the city had been used as