Dynastic History | The Ṭerbāl, Ardashir-Khurra — A Circle of Twenty Sectors and the Tower It Was Set Out From

After defeating the last Parthian king, Ardashir I laid out a city on the plain below the gorge. It was called Ardašīr-Ḵorra, "the glory of Ardashir", and locally Gōr; C. E. Bosworth places its foundation on the site of that victory, probably in 224. The plan was a circle. Survey and excavation give a diameter of 1,950 metres, divided into twenty sectors by twenty radial streets crossed by concentric ones, with gates at the four cardinal points and a ditch outside the wall.

At the centre stands the Ṭerbāl: a pier of rough stone masonry nine metres square and over thirty metres high, the core of a stair-tower. It watched the plain, and before that it was the fixed point the geometry was set out from. Beside it are the remains of the Taḵt-e Nešīn, a cubical building of dressed stone that carried a brick dome fourteen metres across, most probably Ardashir's fire temple.

The medieval geographers who described the circle — Eṣṭaḵrī, Ebn Ḥawqal, Ebn al-Balḵī, Masʿūdī — wrote centuries afterwards and mixed measurement with legend, but the ground has confirmed the plan they reported. What the Sasanian inscriptions record is victories and titles, not the labour that raised the walls; no construction account survives.

The name did not last either. In New Persian gōr had come to mean grave, and in the tenth century the Buyid ruler ʿAżod-al-Dawla renamed the place Fīrūzābād, city of victory. The circle is farmland now, cut by the field boundaries and irrigation that UNESCO lists among the threats to it. The tower stands in the middle of it, with the modern town out on the plain to the east.

📸 Cover: the Ṭerbāl at the centre of the circular city of Gōr, at night, NasirGhoreishi, CC BY-SA 4.0 via Wikimedia Commons