for help against the impending siege of Constantinople by Ottoman Sultan Mehmed the Conqueror. Nicholas issued the bull Dum Diversas (18 June 1452) authorizing King Alfonso V of Portugal to "attack, conquer, and subjugate Saracens, pagans and other enemies of Christ wherever they may be found". Issued less than a year before the Fall of Constantinople in 1453, the bull may have been intended to begin another crusade against the Ottoman Empire. Furthermore, the bull Romanus Pontifex (1455) gave the right of taking for reason of punishment for crime saracens (who, as Muslims in general were slavers themselves, often capturing Christians) and pagans as perpetual slaves. With the realization that the Americas represented regions of the Earth of which the Europeans were not aware earlier, there arose intense speculation over the question whether the natives of these lands were true humans or not. Together with that went a debate over the (mis)treatment of these natives by the Conquistadores and colonists. The main impetus for Sublimis Deus was a council held by prominent Missionaries in Mexico in 1537, including Archbishop Juan de Zumárraga, Bartolomé de Las Casas and Bishop of Puebla Julián Garcés. They discussed the methods of converting the natives, especially the Franciscan practice of mass baptism. Basing a recommendation to the pope on Las Casas' treatise on how to convert the Indians, "De Unico Vocationis Modo", they sent a letter to Rome with Dominican friar named Bernardino de Minaya (born c. 1489). In 1537, Minaya arrived in Rome and pleaded his case on behalf of the Indians. In response, Paul issued Sublimis Deus on June 2, 1537. "Pastorale officium", a papal brief apparently used in conjunction with the Sublimis Deus by Minaya, declared automatic excommunication for anyone who failed to abide by the new ruling. Stogre (1992) notes that Sublimis Deus is not present in Denzinger, the authoritative compendium of official teachings of the Catholic Church, and that the executing brief for it ("Pastorale officium") was annulled the following year. Davis (1988) asserts it was annulled due to a dispute with the Spanish crown. The Council of The West Indies and the Crown concluded that the documents broke their patronato rights and the Pope withdrew them, though they continued to circulate and be quoted by La Casas and others who supported Indian rights. According to Falkowski (2002) Sublimis Deus had the effect of revoking Pope Alexander VI's bull Inter