Callixtus III (Inter Caetera quae in 1456), Sixtus IV (Aeterni regis in 1481), and Leo X (1514). During the Reconquista of the late 15th century, many Muslims and Jews were enslaved in Iberia (especially after the Castilian-Aragonese victory in the Granada War of 1482–1492). Following Columbus's first voyage to the Americas, the bulls issued by Nicholas V, Callixtus III and Sixtus IV became the models for subsequent major bulls by Pope Alexander VI, such as Eximiae devotionis (3 May 1493), Inter Caetera (4 May 1493) and Dudum Siquidem (23 September 1493), in which similar monopolies were conferred upon Spain relating to the newly discovered lands in the Americas and the indigenous peoples of the Americas. In 1537 – after denunciations of slavery by Fr. Bartolomé de las Casas, a former colonist in the West Indies turned Dominican – Pope Paul III revoked the previous authority to enslave indigenous people of the Americas with the bulls Sublimus Dei (also known as Unigenitus and Veritas ipsa) and Altituda divini consolii, as well as a brief for the execution of Sublimus Dei – a document known as Pastorale officium. Sublimus Dei, in particular, was described by Hans-Jürgen Prein (2008) as the "Magna Carta" for the human rights of indigenous people in its declaration that "the Indians were human beings and they were not to be robbed of their freedom or possessions". In addition, Pastorale officium decreed a penalty of excommunication for anyone failing to abide by the bulls. Following a dispute between the papacy and the government of Spain, Pastorale officium was annulled the following year, in Non Indecens Videtur. However, the documents issued by Paul III continued to circulate and to be quoted by those opposed to slavery. According to James E. Falkowski, Sublimus Dei "had the effect of revoking" Inter Caetera, but left intact the "duty" of colonists, i.e. "converting the native people". A series of bulls and encyclicals in 1435, 1537 and 1839 from several popes condemned both slavery and the slave trade. The Quakers were the first churchmen to openly oppose the English slave trade. They were followed in 1766 by a senior Church of England figure, William Warburton, the Bishop of Gloucester and close friend of anti-slavery champion Lord Mansfield, who, in a "courageous" stand, publicly condemned the practices of the Anglican Society for the Propagation of the Gospel whose possessions included 2 slave plantations in Barbados that