Pope Nicholas V Grants Portugal Religious Cover to Enslave Africans
The bull Romanus Pontifex declares sub-Saharan Africans subject to perpetual slavery and hands Portugal a trading monopoly
Quick facts
- Date
- January 8, 1455
- Issued by
- Pope Nicholas V
- Beneficiary
- King Afonso V of Portugal
- Preceded by
- Dum Diversas, 1452
What happened
On January 8, 1455, Pope Nicholas V issued the papal bull Romanus Pontifex, following an earlier bull, Dum Diversas, in 1452. Together the two documents granted King Afonso V of Portugal the right to invade, conquer, and enslave non-Christian peoples encountered south of Cape Bojador on the West African coast, and gave Portugal an exclusive claim over trade there against other Christian powers. The bull framed enslavement as a vehicle for converting Africans to Catholicism, language church leaders used to argue slavery served as what one Lowcountry Digital History Initiative essay calls a natural deterrent and Christianizing influence on people they described as barbarous. No European army ever occupied the territory the bull described. Portugal instead pursued the trade it authorized through commerce, buying captives from African merchants and rulers along existing trade networks rather than by conquest.
Why it matters
Romanus Pontifex gave the Portuguese crown, and by extension the merchants it licensed, a religious and legal justification that outlasted the pope who wrote it. Later slaving nations, including Spain, cited this framework of Christian dominion over non-Christian peoples to defend their own participation in the trade for the next three centuries, long after the theological argument had been challenged by other churchmen.
How we know
The text of Romanus Pontifex survives in the Arquivo Nacional da Torre do Tombo in Lisbon; the Lowcountry Digital History Initiative's exhibit on Iberian slavery quotes and analyzes the bull directly, tracing how it was invoked in later Portuguese and Spanish slaving law.
Sources
- Lowcountry Digital History Initiative, College of Charleston. Pope Nicolas V and the Portuguese Slave Trade · Primary source (author-declared)ldhi.library.cofc.edu · Cited as a "primary" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
- Lowcountry Digital History Initiative, College of Charleston. Pope Nicolas V and the Portuguese Slave Trade · Reputable sourceldhi.library.cofc.edu · The domain "ldhi.library.cofc.edu" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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Part of a timelineThe Atlantic Slave Trade29 events · Four centuries in which European traders forced an estimated 12.5 million Africans onto ships bound for the Americas, and the enslaved people, revolts, and abolitionists who fought it from the first crossing to the lastView all →