Hasan-i-Sabah was born in northern Persia around 1050 and died in 1124. He was an Ismaili missionary (or dai) who founded the Nizari Ismailis after the usurpation of the Fatimid Imamate by the military dictator of Egypt. It may be said that Hasan founded and operated the world's most successful mystical secret society, while building a political territory in which to maintain his independence. The small empire he created would be home to him, his followers and their descendants for 166 years. Today, under the leadership of the Aga Khan, the Nizari Ismailis are one of the preeminent Muslim sects in the world, numbering some twenty million members in twenty-five countries. The mediaeval Nizaris were, also, known as Assassins or Hashishim. They became embedded in European consciousness because of their contact with the Knights Templar and other Crusaders and visitors to the Near East. Several Europeans reported back with strange (and largely false) tales of the Assassins. In the fourteenth century, they were widely popularised by the famed Venetian traveller and writer, Marco Polo, in The Travels of Marco Polo. He added a whole new level of myth in his account of the sect (included in this volume along with extensive commentary). Of greatest interest is the idea that the Assassins were the spiritual initiators of the Knights Templar. If this is true, Hasan-i-Sabah would be in part responsible for the European Renaissance that would reclaim the spiritual centrality of the Hermetic writings and the Gnostic/Esoteric trends that continue to this day.