The Illuminati Order was a secret organisation founded in Ingolstadt, Germany on May 1, 1776 by Adam Weishaupt, with the ultimate goal to rule the world through assasination, bribery, blackmail, the control of banks and other financial powers, the infiltration of governments, and by causing wars and revolutions to move their own people into higher positions in the political hirarchy.
The enemies of the Illuminati were the monarchs of Europe and the Church. The French revolution (1788) and the Russian revolution (1917) are said by some to be caused by the Illuminati conspiracy, although the order was officially shut down in 1790. Very few historians give credence to these views, regarding such claims as the products of over-fertile imaginations.
There is a three-book science fiction series named Illuminatus! by Robert Shea and Robert Anton Wilson, published in the 1980s and regarded as a cult classic in the hacker community. Part 1: The Eye in the Pyramid; Part 2: The Golden Apple; Part 3: Leviathan.
Many people became aware of the story of the Illuminati through the computer game Deus Ex.