The Crusader - Michael Alexander Eisner
This is another bookswap experience, because I'm not really a big reader of 'straight' historical fiction. However the the fact that our protagonists are Spanish crusaders added to a degree of interest in reading this book.

The Crusader is about two men, the ambitious low-born cleric Brother Lucas and Francisco de Montcada, heir to a massive estate. The two men first meet when Francisco is sent for his education to the monastery where Lucas has grown up. After Francisco leaves, he becomes a crusader in one of the orders of knights, and it's on his return to Spain that the two men cross paths again, as Francisco is meant to be possessed. It's Lucas' job to heal him, in order that the church can get its hands on a massive financial payment from Francisco's grateful father.

First off, I should probably say that the fact this book is all told in the first person is always going to be an issue for me. Having been to some of the places the book talks about, there's certainly an element of the local atmosphere about The Crusader, but sadly Eisner very much telegraphs the shock-horror revelation he has planned and it therefore loses much of its impact.