I am trying to recall the name and author of a work of historical fiction.  It is set on an island kingdom in the Mediterranean.  A Muslim nobleman ends up on the island and is taken prisoner as an “infidel.” He refuses to convert to Christianity despite the threat of execution by an Inquisitor.  He warns his captors that his nation will send a fleet to rescue him and destroy them if he is harmed or killed. Ultimately he is put to death.  At the end of the book a fleet is on the horizon in search of the now dead leader.  Destruction of the island kingdom is assured.  Can someone help me call the title and author of this wonderful and thought provoking tale?  Thanks.