Level: MediumIn 1066, only Catholicism and Ash'arism satisfy the conditions for declaring Great Holy Wars, and the Pope will unlock this ability in 1095, before the Caliph. Thus starting as a Catholic in 1066 and participating in the first Crusade is the quickest way to get this achievement. You can combine this with the
FIRST OF THE CRUSADER KINGS Achievement from the Nothern Lords DLC.
Credit to
Bayek von Kuwaq on Steam for his
guide.