Not quite all anyone needs to know about Christianity.

An Edict issued by pope Nicholas V in 1452
granted the Portuguese king Alfonso V the right to
“invade, search out, capture, vanquish, and subdue
all Saracens [Muslims] and pagans whatsoever,
and other enemies of Christ wheresoever placed,
and the kingdoms, dukedoms, principalities, dominions,
possessions, and all movable and immovable goods
whatsoever held and possessed by them
and to reduce their persons to perpetual slavery”.