Iraj Castle
Native name قلعه ایرج (Persian)
Qaleh Iraj, Iraj Citadel
The eroded walls of the Iraj Castle
Type	Fortification
Etymology	Mythical kingIraj
Location	Near Varamin,Sasanian Empire (modern-dayAsgarabad-e Abbasi,Iran)
Coordinates	35°20′35″N51°40′51″E / 35.3431°N 51.6808°E /35.3431; 51.6808
Area	190 hectares (470 acres)[1]
Elevation	1,440 metres (4,720 ft)
Height	25 metres (82 ft)
Built	4th or 5th century AD
Built for	Sasanian army
Original use	Military base
Current use	Agriculture
Architectural style	Sasanian
Governing body	Cultural Heritage, Handicrafts and Tourism Organization of Pishva County
Location of the Iraj Castle on the map of Iran

Iraj Castle (Persian:قلعه ایرجQal'eh Iraj)^[2] is a fortification built in 4th or 5th century AD in the central region ofRay,Sasanian Empire, near modern-dayAsgarabad-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.

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 royalSasanian architecture. The structure was further protected by aditch 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.^[3][4][5]

• 
  The eroded walls
• 
  Remains of a room in the northern wall
• 
  Remains of chambers north west of the site.

Popular beliefs identify the structure with the Citadel of Varena mentioned in the holy Zoroastrian textVendidad.^[6] 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 andbullae suggest it was occupied and abandoned within theSasanian 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.^[3]

Qaleh Iraj is the largest pre-modern, non-urban permanent fortification in South-west Asia, Europe and Africa. Other similarly vast military structures areZadian in modernAfghanistan and the early Sasanian siege camp atHatra, modernIraq. The general design of Qaleh Iraj, i.e. massive fortifications and a massive empty interior, is similar to the Sasanian campaign basesQaleh Pol Gonbad in theGorgan Plain andTorpakh Kala nearDerbent. Another example isQaleh Kharabeh near theGreat 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 BCKazakl'i-Yatkan/Akchakhan-Kala inChorasmia.^[3]

• 
  The plan ofHatra. Note the vastcontravallation.
• 
  Zadian, Afghanistan

A total of about 50,000 warriors could have comfortably occupied the structure. The rooms may have housed the permanent garrison, while the open interior space was occupied temporarily.^[3]

Qaleh Iraj was probably built in response to northern nomadic invaders which, on some occasions, penetrated deep into the Sasanian territory. It probably functioned mainly as a central base for military operations elsewhere, especially at the northern frontiers. It may have been used for military training and/or military assemblies as well. The 36 hectares (89 acres) campaign base atGabri Qaleh nearGonbad-e Kavus was built in the same period. Both thus predate theGreat Wall of Gorgan. These Sasanian campaign bases may have been built before the northern frontiers were protected by the linearSasanian defence lines.^[3]

The region Ray was suitable as a central base from several aspects. Sitting at the center ofGreater Iran and on a central communication hub, it was always a militarily significant region. Plus, it was also the base of the powerfulHouse of Mihran during the Sasanian period.^[3]

Parts of the walls have been eroded, and out of the four gates, only the main, southern gate remains today. Iraj Castle is considered as the world's largest mud-brick fort with a height of 50 feet and an area of 200 hectares.^[7][4]

There have been attempts by theCultural Heritage, Handicrafts and Tourism Organization of Iran in 2008 to designate it as aUNESCO World Heritage Site, but the efforts were abandoned due to "serious shortcomings" and the situation of the area, including the agricultural activities of local farmers in the interior of the structure.^[6]

Illegal excavation have damaged parts of the walls. On 26 May 2018, an illegal excavation was reported in the Northern Gate. Majid Zhaleh, the head of the Cultural Heritage, Handicrafts and Tourism Organization of Pishva County, stated that his organization lacks enough manpower.^[8]

• 
  Contemporary farms inside the castle.
• 
  A contemporary water canal dug by farmers.

• Quadrangular castle
• Caravanserai
• Campus Martius
• List of castles in Iran

Wikimedia Commons has media related toIraj Castle.

• Castles in Iran
• Sasanian castles
• Buildings and structures in Tehran province
• National works of Iran
• Tourist attractions in Tehran province
• 4th-century fortifications
• 5th-century fortifications

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