Nicholas V, European Treaties bearing on the History of the United States and its Dependencies to 1648 (1917)
“ It is probable that King Alfonso deemed the time especially propitious for a settlement of the dispute over the proprietorship of Morocco, Guinea, and the Guinea trade. In attempting to establish his claims, he would naturally seek aid from the Pope, for that potentate's independent position made him the arbitrator between nations, while his spiritual authority, in particular his powers of excommunication and interdict, gave weight to his decisions. ”
