Qaleh Pol Gonbad no relation Sasanian campaign base
Iraj Castle (Persian: قلعه ایرج Qal'eh Iraj) is a fortification built in 4th or 5th century AD in the central region of Ray, Sasanian Empire, near modern-day Asgarabad-e Abbasi, Iran. The monument is known for its peculiar design: large defensive walls with embedded rooms and arches, with towers at regular intervals, enclosing a vast empty interior of 190 hectares (470 acres).
The design is similar to several other Sasanian campaign bases. The permanent service members supposedly occupied the walls and the rooms inside it, while the empty interior would be occupied by tents or used for training or military assemblies. It probably served as a central military base for operations elsewhere, especially against the incursions of nomadic nations in the north.Description and purpose
The structure consists of an empty area approximately 175 hectares (430 acres), surrounded by a wall 15–22 metres (49–72 ft) in width and up to 25 metres (82 ft) in height. It featured 148 densely spaced towers and four monumental gates. The massive walls contained a wealth of embedded structures: a row of around 828 rooms (circa 12 square metres (130 sq ft) in size) and hundreds of monumental arches, evoking royal Sasanian architecture. The structure was further protected by a ditch around the wall. A population of 2,000-6,000 could have been accommodated in the walls. Despite this strong architectural focus on the walls, there were no permanent buildings in the interior space.Popular beliefs identify the structure with the Citadel of Varena mentioned in the holy Zoroastrian text Vendidad. Archaeological studies suggest it was built probably in the final decades of the 4th century AD or the first quarter of the 5th century AD. Excavated Sasanian-era pottery, ostraca and bullae suggest it was occupied and abandoned within the Sasanian period. The structure's function had been previously described as a city, a military fortress, or a game park for the royal hunt, or of a possible prestige function.Qaleh Iraj is the largest pre-modern, non-urban permanent fortification in South-west Asia, Europe and Africa. Other similarly vast military structures are Zadian in modern Afghanistan and the early Sasanian siege camp at Hatra, modern Iraq. The general design of Qaleh Iraj, i.e. massive fortifications and a massive empty interior, is similar to the Sasanian campaign bases Qaleh Pol Gonbad in the Gorgan Plain and Torpakh Kala near Derbent. Another example is Qaleh Kharabeh near the Great Wall of Gorgan which had accommodated two neatly aligned rows of tents with wide corridors in between, suggesting similar role of the interior space in other bases. Another similar structure is the late third-century BC Kazakl'i-Yatkan/Akchakhan-Kala in Chorasmia.