Pope Nicholas V issued the papal bull, Dum Diversas.
In it he “granted among other things free and ample faculty” to King Alfonso of Portugal “to invade search out, capture, vanquish, and subdue all Saracens, pagans whatsoever, and other enemies of Christ wheresoever placed, and the kingdoms, dukedoms, principalities, dominions, possessions, and all moveable and immoveable goods whatsoever held and possessed by them and reduce their persons to perpetual slavery” and convert all of it to his use and profit.
This papal edict gave profiteering from slavery and theft of Western Africa and its peoples by a Christian monarch the Church’s blessings.