Lambesar Fortress

Qazvin Province, Iran

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Lambesar Fortress, also known as Lambsar or Lamasar, is a large and historically significant castle located in the Alamut region of Qazvin Province, Iran. Originally built during the Sassanid period and widely used in the Seljuk era, it became one of the strongest fortresses of the Ismaili Nizari state under Hasan-i Sabbah.

The fortress is perched on a high rock between two rivers and features two main parts: an inner section with towers, ramparts, and residential buildings, and an outer part containing stables and storehouses. Lambesar played a key role as a military base and stronghold for the Ismailis, resisting Mongol invasions until it fell around 1257 after a cholera epidemic weakened its defenders.

Its massive size and complex structure reflect its strategic importance. Today, the castle remains an important historical and cultural site, with restoration efforts underway to preserve its ruins.