This is a long and rambling novel. While I enjoyed it, I thought that it was a bit overlong for the story line. It could have been shortened a bit without losing anything.
One thing that I did find slightly disconcerting is that this book is a prequel to a series of books that I have not read. When some characters were introduced they were clearly much more important than some others in the book. I assume that this is because they are in the later books [chronologically] in the series. People who have read the books written earlier will think "Aha, I know this chap. He is the one who goes on to do whatever it is he does". But not having read the other books this was all a bit lost on me. Never mind. I guess most people reading this book will have read the other Templar books by Michael Jecks and will be fully on board with it.
The book successfully conjures up the lost world of the crusades and of the military orders. It manages to convey the contemporary attitudes to religion and religious warfare without being condemnatory [which must be a temptation] nor portraying the monastic killers as being overly heroic. We learn a lot about the attitudes of the men and women of the time - on both sides of the divide.
And it is a gripping story with numerous twists and turns. I really must look around for more in this series.