A Nizari Isma'ili Shia state founded by Hassan-i Sabbah after he seized the mountain fortress of Alamut in the Alborz range in 1090; a decentralized theocracy of scattered strongholds across Persia and later Syria, defended by adherents popularly known as the Assassins (Hashashin), who used targeted political killings against Sunni Seljuk and Abbasid rivals.
Systematically reduced by the Mongols under Hulagu Khan, who took Alamut itself in 1256, ending organized Nizari political power in Persia; the remaining Syrian branch persisted a little longer under Mamluk pressure.
The atlas holds 3 border frames for Nizari Ismaili State (Alamut) — the shape you scrub through changes in 1090 · 1195 · 1206.
The classic English-language study of the Nizari Ismaili state and the Assassin legend, verified on Open Library.