No. That hack writer pulled off most of his stuff from a different person's book. The movie was OK but the most glaring non-fact is that the heretic cult in Southern France believed that the soul is trapped in the human body - that's where the celibacy came in - even in marriage.
So these folks would certainly NOT help keep the line of Christ alive.
BTW it was the closest and shortest crusade to go to southern France to wipe them all out.