Order of Assassins in the context of "List of Ismaili castles"

The Mongol invasions of Georgia (Georgian: მონღოლთა ლაშქრობები საქართველოში, romanized: mongholta lashkrobebi sakartveloshi), which at that time consisted of Georgia proper, Armenia, and much of the Caucasus, involved multiple invasions and large-scale raids throughout the 13th century. The Mongol Empire first appeared in the Caucasus in 1220 as generals Subutai and Jebe pursued Muhammad II of Khwarezm during the destruction of the Khwarezmian Empire. After a series of raids in which they defeated the combined Georgian and Armenian armies, Subutai and Jebe continued north to invade Kievan Rus'.

A full-scale Mongol conquest of the Caucasus and eastern Anatolia began in 1236, in which the Kingdom of Georgia, the Sultanate of Rum, and the Empire of Trebizond were subjugated, the Armenian Kingdom of Cilicia and other Crusader states voluntarily accepted Mongol vassalage, and the Assassins were eliminated. Mongol rule in the Caucasus lasted until the late 1330s. During that period, King George V the Brilliant restored the kingdom of Georgia for a brief period before it finally disintegrated due to Timur's invasions of Georgia.

The Nizari state (the Alamut state) was a Nizari Isma'ili Shia state founded by Hassan-i Sabbah after he took control of the Alamut Castle in 1090 AD, which marked the beginning of an era of Ismailism known as the "Alamut period". Their people were also known as the Assassins or Hashashins.

The state consisted of a nexus of strongholds throughout Persia and the Levant, with their territories being surrounded by huge swathes of hostile as well as crusader territory. It was formed as a result of a religious and political movement of the minority Nizari sect supported by the anti-Seljuk population. Being heavily outnumbered, the Nizaris resisted adversaries by employing strategic, self-sufficient fortresses and the use of unconventional tactics, notably assassination of important adversaries and psychological warfare. They also had a strong sense of community as well as total obedience to their leader.

Hasan-i Sabbah also known as Hasan I of Alamut, was a religious and military leader, founder of the Nizari Ismai'li sect, Order of Assassins, as well as the Nizari Ismaili state, ruling from 1090 to 1124 AD.

Alongside his role as a leader, Sabbah was a scholar of mathematics, most notably in geometry, as well as astronomy and philosophy, especially in epistemology. It is narrated that Hasan and the Persian polymath Omar Khayyam were close friends since their student years. He and each of the later Order of Assassins' leaders came to be known in the West as the Old Man of the Mountain, a name given by Marco Polo that referenced the sect's possession of the commanding mountain fortress of Alamut Castle.

List of assassinations and assassination attempts attributed to the Assassins (the Nizaris of Alamut), active in Western Asia, Central Asia, and Egypt, in the 11th through 13th centuries.