Today's Arab assassins are the spiritual inheritors, if not lineal descendents, of a group of terrorists who called themselves the Order of Assassins ( = Arabic Al-Hashashun = user of hashish). It was a secret organization of the Ismaili sect, which in turn is part of Shi'i Islam. You may remember that the high-living Aga Khan, who is leader of the Ismaili sect. Many Iranians believed that the Ayatollah Khomeini was the hidden 12th Imam or leader of Shi'i.

The Assassins were famous for their mindless obedience to the chief and for their use of murder and assassination as a political tool. It has been rumored that the leader used hashish and possibly other drugs to obliterate personal willpower and to imbue the would-be murders with unlimited bravery. Count Henry of Champagne in 1194 visited the fortress Alamut and told the story that, to demonstrate that obedience, the chief of the Assassins merely gestured to two young followers who immediately leapt off a tower to their death.

The founder of the sect was Hasan ibn al-Sabbah (c.1090) who established the Order from the mountain fortress of Alamut, located south of the Caspian Sea. As the Order gained power through intimidation and terrorism, it extended its influence through Persia and Syria until no one of political importance was safe from their devious methods of eliminating their enemies.

The order operated much like some of the esoteric groups in Europe. Advancement through the grades was marked by an initiation more deeply into the secrets of the order. There are reports that the one secret of a degree was that the truths of the previous degree were untrue. Hasan's philosophy was summed up in the motto "nothing is real and everything is permissible." The highest degree contained those devotees eager for martyrdom in the open assassination of an enemy.

The Mongol Hulagu Khan in 1256 destroyed their fortresses and eradicated most of the sect in Persia. The armies of the Mamluk sultan of Egypt delivered a similar blow to the Syrian groups, which had come into contact with the Crusaders. Small assemblies of Assassins exist today, particularly in north Syria.

Stories brought back by the Crusaders and descriptions written by Marco Polo introduced the Assassins into European folklore. The term assassin came into English and is used today to mean murderer and particularly one who kills for political motives. A few modern groups, both occult and political, claim at least a spiritual connection to the Order.


References:
http://www.globale.net/~heritage/mirrors/26_alamut/ass-sys.htm
http://nepenthes.lycaeum.org/Ludlow/Texts/assassin.html
http://www.weirdload.com/hasan.html
http://ismaili.net/~heritage/mirrors/20_secrets/30cl.htm
http://homepage.ntlworld.com/anthony.campbell1/assassins/index.html