|Lamasar Castle||Lamasar Fortifications|
Lamasar, or Lanbasar, was probably the largest of the Ismaili castles. It measured 440 metres from north to south and 192 metres from east to west. The fortress was located in the Rudbar district of the Upper Shahrud, 40 kilometres northeast of Qazwin and west of Alamut. After its capture, Kiya Buzurg Ummid (d. 532/1138), who was appointed by Hasan Sabbah (d. 518/1124) as its governor, rebuilt the fortress into a major stronghold using local labour, equipping it with ample water resources and cisterns, which are still in existence, and atmospheric gardens. Its sloping terrain was utilised as a water catchment area and every advantage was taken of the steep cliffs running around the top of the castle.
- Kiya Buzurg Ummid captured the castle from Rasamuj and his relations in Dhu’l-Qa‘da 489/November 1096 or 495/1102 according to Juwayni.
- Lamasar was besieged for eight years between 503–511/1110–1118 by Saljuq forces. During this time, Hasan Sabbah sent the women of his family to safer places such as the castle of Girdkuh.
- Lamasar was the last of the fortresses to fall to the Mongols in the Rudbar region. It held out for over a year before cholera broke out and killed the bulk of the garrison. Those who survived finally surrendered in 655/1257. Subsequently, Lamasar and Girdkuh were placed under the supervision of different Mongol units and commanders.