Alamut Castle: Location, History and the Fall of 1256

Updated: 6 November 2026

Short answer

Alamut Castle stands near the village of Gazor Khan in Qazvin province, Iran, about 200 km from Tehran. Hasan-i Sabbah took it by infiltration in 1090. It was the centre of the Nizari Isma'ili state until it passed to the Mongols in 1256. It joined the UNESCO World Heritage List in July 2026.

Capturing the castle

Daftary describes the seizure of 1090 as a "clever plan of infiltration". The TDV entry dates his settling there and founding the state to 6 Rajab 483 (4 September 1090). The popular account adds that Hasan won over the garrison and bought out its holder, Mahdi, for 3,000 gold dinars. That detail is a report rather than a settled fact.

Hard to conquer, but not unconquerable

The castle sits on a narrow rock mass overlooking the Alamut valley, whose approaches are difficult. Hasan improved cultivation and irrigation and built storehouses. Seljuk campaigns of 1091, 1109 and 1117-18 failed; the last siege lifted when Sultan Muhammad Tapar died.

Its fall in 1256 came through surrender. As Hulegu's campaign closed in, the imam Rukn al-Din Khurshah gave himself up and ordered his castles to yield. The Mongols then dismantled the fortress. It was briefly retaken in 1275.

The library

Hasan founded a library that grew until 1256. The historian Juvayni, serving the Mongols, inspected it, set aside the works he selected, and the rest were destroyed. He alone decided which works counted as heretical. No full catalogue survives, so popular claims about its size are not verifiable.

Frequently asked questions

Where is Alamut Castle located?: Near Gazor Khan in Qazvin province, in the western Alborz range, at about 36°26′41″N, 50°35′10″E.
How did Hassan Sabbah capture Alamut Castle?: Through a planned infiltration in 1090, without a siege, by winning over people in and around the castle.
Why was Alamut Castle so difficult to conquer?: Its site, the difficult valley approaches, stored supplies and allied castles, along with Seljuk succession struggles.
What happened to Alamut Castle in 1256?: It was handed over to the Mongols on Khurshah's orders and dismantled, and its library was largely destroyed.
Who destroyed the library of Alamut?: It was destroyed after the Mongol takeover; Juvayni decided which works to keep.
Is Alamut a UNESCO World Heritage site?: Yes. "Alamut Castle and Related Fortifications" was inscribed on 26 July 2026 at the 48th session in Busan, according to press reports.

Sources

Medieval authors such as Juvayni, Rashid al-Din and Ibn al-Athir are cited here through the listed studies, not directly. Prepared by the hasansabbah.com editorial team.