Blue Flame - K. M. Grant

Up in the hills of Languedoc, Raoul de Bertrand tends to a small blue flame in a filigree box, a flame lit at the moment of Christ's death when the veil of the Temple was rent in two. Raoul has been hiding here since, as a boy, he inadvertently shot Richard the Lionheart with his crossbow, a crime for which his father was killed.
It was for this flame that Richard the Lionheart came to Chalus Chabrol, for the possessor of the flame appears to have the authority of God Himself in all his actions. Sir Bertrand, facing certain death, entrusted the flame to Raoul, telling him this is the flame of salvation and is waiting to be claimed by a good man who will use it to heal rather than destroy. It is essential, therefore, that the flame is given to the right person. His father has been waiting for years for that person, without success, and it is his dying wish that Raoul succeeds. Raoul promises.
By 1242, war has all but broken out between the Catholics who control northern France and the Languedoc region, where many religions co-exist in peace. This battle finally draws Raoul out of hiding, as he becomes aware, the fight is for his blue flame.
Making friends with a young couple caught on either side of the conflict, Rauol reveals his secret to Raimon, a Cathar, and Yolanda, a Catholic. As the conflict grows bloodier by the day, and Raimon is accused of murdering numerous Catholics, including Yolanda's uncle, will their love survive? And more importantly, will they?