Assassin (əsăsˈĭn) [key], European name for the member of a secret order of the Ismaili sect of Islam. They are known as Nizaris after Nizar ibn al-Mustansir, whom they supported as caliph; the European term Assassin is derived from the Arabic for "users of hashish." The members of the order were distinguished by their blind obedience to their spiritual leader (known in the West as the Old Man of the Mountain) and by their use of murder to eliminate foes.
The order was founded by Hasan ibn al-Sabbah when he gained control (c.1090) of the mountain fortress of Alamut, located S of the Caspian Sea. The order spread over Persia and Syria, gaining control of many strongholds, and it soon inspired terror throughout the Muslim world. Members were organized into strict classes, according to degree of initiation into the secrets of the order. The most important of the classes were the devotees, who sought martyrdom and were the instruments of assassination.
Hasan and the grand masters who ruled the order after him wielded great political power until the coming of the Mongols. Hulagu Khan attacked and destroyed (1256) their fortresses and massacred most of the Persian branch of the sect. The Syrian branch, with which the Crusaders came in contact, suffered a similar fate at the hands of Baybars, the Mamluk sultan of Egypt. Only scattered groups of the order survived; they are said to persist today, particularly in N Syria. Tales of the Crusaders and the writings of Marco Polo brought the Assassins and the Old Man of the Mountain into European folklore. The term assassin came into English and is used today to mean murderer, particularly one who kills for political motives.
See B. Lewis, The Assassins (1967); E. Franzius, History of the Order of Assassins (1969).