The Mongols had a difficult time subduing the Nizari Ismailis until they were able to attack Alamut Castle and capture their Imam.
Description
Alamut Castle
Alamut (Persian: الموت, transliterated Alamūt) was a mountain fortress located in the South Caspian province of Daylam near the Rudbar region in Iran, approximately 100 km (60 mi) from present-day Tehran, Iran. The name means "Eagle's Nest.":23