The Saracen: Land of the Infidel is the first volume in a two-part historical novel, set in the 13th century during the crusades. The story portrays an English-born man named David, who is captured as a very young child and sold into slavery to Baibars, a Mamluk officer. He becomes a devout believer in Islam and takes the Arabic form of his name and the surname of a convert, Daoud ibn Abdullah. He develops into a gifted warrior and assassin. He is sent to the Papal Court in Orvieto in the 13th century as a spy, in order to foil an alliance between the Christian West and the Mongolian descendants of Genghis Khan to exterminate the Muslim faith and capture the Holy Land.
Daoud was also trained by the Hashishyya, a heretical Islamic order. One of the many spellings of their name, Hashshashin, is where we derive the modern word "assassin". The author spends considerable time discussing their techniques and philosophy, and it is a major theme of the book.
Also by Robert J. Shea on obooko:
The Saracen: Book Two, The Holy War
All Things Are Lights