Dum Diversas [English: 'Until different'] is a papal bull issued on 18 June 1452 by Pope Nicholas V, that is credited by some with "ushering in the West African slave trade." It authorized Afonso V of Portugal to conquer Saracens and pagans and consign them to "perpetual slavery." Pope Calixtus III reiterated the bull in 1456 with Etsi cuncti, renewed by Pope Sixtus IV in 1481 and Pope Leo X in 1514 with Precelse denotionis. The concept of the consignment of exclusive spheres of influence to certain nation states was extended to the Americas in 1493 by Pope Alexander VI with Inter caetera.
Issued one year before the Fall of Constantinople in 1453, the bull may have been intended to begin another crusade against the Ottoman Empire. Nicholas V's nephew, Loukas Notaras, was Megas Doux of the Byzantine Empire. Some historians view these bulls together as extending the theological legacy of Pope Urban II's Crusades to justify European colonization and expansionism, accommodating "both the marketplace and the yearnings of the Christian soul." Dum Diversas was essentially "geographically unlimited" in its application, perhaps the most important papal act relating to Portuguese colonization.
Dum Diversas provided:
|“||"We grant you [Kings of Spain and Portugal] by these present documents, with our Apostolic Authority, full and free permission to invade, search out, capture, and subjugate the Saracens and pagans and any other unbelievers and enemies of Christ wherever they may be, as well as their kingdoms, duchies, counties, principalities, and other property [...] and to reduce their persons into perpetual slavery.||”|
In 1537 pope Paul III condemned "unjust" enslavement of non-Christians in Sublimus Dei  but he sanctioned slavery in Rome in 1545, the enslavement of Henry VIII in 1547 and the purchase of Muslim slaves in 1548. In 1686 the Holy Office limited the bull by decreeing that Africans enslaved by unjust wars should be freed.
Dum Diversas, along with other bulls such as Romanus Pontifex (1455), Ineffabilis et summi (1497), Dudum pro parte (1516), and Aequum reputamus (1534) document the Portuguese ius patronatus. Pope Alexander VI, a native of Valencia, issued a series of bulls limiting Portuguese power in favor of that of Spain, most notably Dudum siquidem (1493).
See also 
- Love, David A. June 16, 2007. "The Color of Law On the Pope, Paternalism and Purifying the Savages." ZNet.
- Davenport, Frances Gardiner, and Paullin, Charles Oscar. 1917. European Treaties Bearing on the History of the United States and Its Dependencies to 1684. Carnegie Institution of Washington. p. 12. A large excerpt of the bull, in Latin, can be found in Davenport, p. 17, Doc. 1, note 37.
- Hayes, Diana. 1998. "Reflections on Slavery." in Curran, Charles E. Change in Official Catholic Moral Teaching.
- Sardar, Ziauddin, and Davies, Merryl Wyn. 2004. The No-Nonsense Guide to Islam. Verso. ISBN 1-85984-454-5. p. 94.
- Hart, Jonathan Locke. 2003. Comparing Empires: European colonialism from Portuguese expansion to the Spanish-American War. Palgrave Macmillan. ISBN 1-4039-6188-3. p. 18.
- Bourne, Edward Gaylord. 1903. The Philippine Islands, 1493-1803. The A.H. Clark company. p. 136.
- Eaglestone, C.R. 1878. The siege of Constantinople, 1453. p. 7.
- Hood, Robert Earl. 1994. Begrimed and Black: Christian Traditions on Blacks and Blackness. Fortress Press. ISBN 0-8006-2767-9. p. 117.
- Grewe, Wilhelm Georg. 2000. The Epochs of International Law. Walter de Gruyter. ISBN 3-11-015339-4. p. 230.
- "The Catholic Church and Slavery", J. F Maxwell, 1975, Barry-Rose Publishers
- Desai, Guarav Gajanan, and Nair, Supriya. 2005. Postcolonialisms: An Anthology of Cultural Theory and Criticism. Rutgers University Press. ISBN 0-8135-3552-2. p. 52.
- Mudimb̂ae, Valentin Yves, and Mudimbé, Vumbi Yoka. 1994. The Idea of Africa. Indiana University Press. ISBN 0-253-20872-6. p. 31.