Crusade by Robyn Young

Second Hand 

"Meanwhile, in Egypt, Sultan Baybars is caught in a power struggle. His eldest son, and heir to the kingdom, has become involved in the dangerous designs of the insidious soothsayer, Khadir, While Baybars wants to lake on the mighty Mongol empire, Khadir and others want to destroy the Christians once and for all. With the sultan's son scheming against his own family, old sears of the Crusades are quickly uncovered and new wounds appear." "As war looms, Will is torn between his oath as a Templar, his secret role in the Brethren and his duty to Elwen, the woman he loves but is forbidden to marry. And when his old friend - and foe - Garin de Lyons arrives on a mission for King Edward, Will's life begins a devastating slide towards chaos and destruction."--BOOK JACKET.