Romanus Pontifex
Romanus Pontifex (from Latin: "The Roman Pontiff") is the title of at least three papal bulls: One issued in 1436 by Pope Eugenius IV; A second issued on September 21, 1451, by Pope Nicholas V, relieving the dukes of Austria from any potential ecclesiastical censure for permitting Jews to dwell there; Another in 1455 by Nicholas V praising Catholic King Afonso V of Portugal for his battles against the Muslims, endorsing his military expeditions into Western Africa and instructing him to capture and subdue all Saracens, Turks, and other non-Christians to reduce their persons to perpetual slavery. The Church leaders argued that slavery served as a natural deterrent and Christianizing influence to "barbarous" behavior among pagans.