Which ones?
>Holy Lands
Sem-important noblemen take up arms to fight for the Roman Catholic Church, and perhaps acquire personal wealth, as well as occasionally kill partially-allied Byzantines, times 14.
>European
Unimportant noblemen take up arms to fight for the Roman Catholic Church against men who are also members of the Roman Catholic Church trying to defend a very small number of men, women and children who are not members of the Roman Catholic Church from the unimportant noblemen who took up arms to fight for the Roman Catholic Church, times 5, maybe.
>Northern
Relatively recently converted unimportant noblemen take up arms to fight for the Roman Catholic Church against the military forces of the unconverted Baltic and Finnic countries of Northern Europe, as well as kill a few Eastern Orthodox people, times 5-ish.
>Popular
Numbskulls go out into the wilderness and die, times we don't exactly know, do we?
>Reconquista
The Spanish try to assert themselves as a world power, become buddy buddies with the Roman Catholic Church, and rescue their long lost great-great-great-great-great… grand cousins from Islam and succeed brilliantly at basically everything, except for saving them, because they might have been made into slave soldiers to fight for Islam, similar to the mamelukes and janissaries.