|Fortress of Girdkuh||Fortress of Girdkuh|
One of the chief Ismaili strongholds in Persia, the fortress of Girdkuh, situated near Damghan, is built upon a conical peak in the Alburz mountain range. Controlling the main east-west trade route to Mashhad, the castle was surrounded by a triple ring of forts making its position seemingly impregnable. Nizari leaders, including Hasan Sabbah (d. 518/1124), often sent their families to Girdkuh for refuge. Girdkuh was the last Nizari stronghold in Persia to surrender to the Mongols, holding out against a Mongol siege for 17 years.
- Girdkuh was acquired in 491/1098 through the efforts of Ra’is Mu’ayyad al-Din Muzaffar, originally an officer in Saljuq service who had been secretly converted to Ismailism.
- In Rabi‘ I 651/May 1253, Hülegü appeared at the head of some 5,000 men at the foot of Girdkuh, where he erected walls and other siege works around the stronghold.
- Girdkuh remained the last Nizari outpost in Persia. Its garrison finally yielded from want of provisions in 669/1270. It was later placed, with Lamasar, under the supervision of Mongol commanders and units.