First of the Crusader Kings

Needs Northern Lords (and there are reports of it failing precisely because the DLC was disabled - check your playset before starting). You need North Germanic heritage (any culture in it, or Norman) and to be Catholic, then join the very first Crusade as an attacker the moment the Pope calls it - historically around 1100 from a 1066 start, give or take. So: start 1066 as a North Germanic ruler, convert to Catholicism if needed, keep the save achievement-valid, and pledge immediately at the declaration. Stay on the attacker side to the end. If it succeeds, For the Faith! pops in the same war.