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
Deioces the Ecbatana Hill, was the true place of the ancient city of Ecbatana. Some historians, including Henry Rawlinson, believe that the Ecbatana mentioned in Herodotus's writings is not the current Hamadan; and the olden Median capital should be searched in Takht-e Soleymān and in the vicinity of Lake Urmia to the south east. But some researchers, like Jacques de Morgan, believe that Herodotus's Ecbatana is the same Hamadan today; and the places of the seven castles of Fort Ecbatana could be identified by the projections on the land and hills. Some Iranologists believe Deioces to be the Hushang in Shahnameh