Site in Azerbaijan, northwest Iran, which was an important religious site in the Parthian, Sassanian and Islamic periods. In the Parthian period, it was surrounded by a mudbrick wall; the Sassanians added a further outer wall of stone. To the Sassanian period belong a palace and a fire temple, which was the focus of a pilgrimage center. The Gushnasp fire was the ancient fire of the Magi (in Media), but it came to be the symbol of the monarchic and religious unity.