By the way, I'm no Calvinist. Your little pet theory fails, when aimed in my direction.
Cordially
However, Fr. Joel Panzer wrote extensively on this and did a fine job of it.
Eugene IV: Sicut Dudum, 1435
On January 13, 1435, Eugene IV issued from Florence the bull Sicut Dudum. Sent to Bishop Ferdinand, located at Rubicon on the island of Lanzarote, this bull condemned the enslavement of the black natives of the newly colonized Canary Islands off the coast of Africa. The Pope stated that after being converted to the faith or promised baptism, many of the inhabitants were taken from their homes and enslaved:
"They have deprived the natives of their property or turned it to their own use, and have subjected some of the inhabitants of said islands to perpetual slavery (subdiderunt perpetuae servituti), sold them to other persons and committed other various illicit and evil deeds against them.... Therefore We ... exhort, through the sprinkling of the Blood of Jesus Christ shed for their sins, one and all, temporal princes, lords, captains, armed men, barons, soldiers, nobles, communities and all others of every kind among the Christian faithful of whatever state, grade or condition, that they themselves desist from the aforementioned deeds, cause those subject to them to desist from them, and restrain them rigorously. And no less do We order and command all and each of the faithful of each sex that, within the space of fifteen days of the publication of these letters in the place where they live, that they restore to their pristine liberty all and each person of either sex who were once residents of said Canary Islands ... who have been made subject to slavery (servituti subicere). These people are to be totally and perpetually free and are to be let go without the exaction or reception of any money."
The date of this Bull, 1435, is very significant. Nearly 60 years before the Europeans were to find the New World, we already had the papal condemnation of slavery as soon as this crime was discovered in one of the first of the Portuguese geographical discoveries.
Eugene IV was clear in his intentions both to condemn the enslavement of the residents of the Canary Islands, and to demand correction of the injustice within 15 days. Those who did not restore the enslaved to their liberty in that time were to incur the sentence of excommunication ipso facto.
With Sicut Dudum, Eugene was clearly intending to condemn the enslavement of the people of the Canaries and, in no uncertain terms, to inform the faithful that what was being condemned was what we would classify as gravely wrong. Thus, the unjust slavery that had begun in the newly found territories was condemned, condemned as soon as it was discovered, and condemned in the strongest of terms.
Paul III: Sublimis Deus, 1537
The pontifical decree known as "The Sublime God" has indeed had an exalted role in the cause of social justice in the New World. Recently, authors such as Gustavo Gutierrez have noted this fact: 'The bull of Pope Paul III, Sublimis Deus (June 2, 1537), is regarded as the most important papal pronouncement on the human condition of the Indians." It is, moreover, addressed to all of the Christian faithful in the world, and not to a particular bishop in one area, thereby not limiting its significance, but universalizing it.
Sublimis Deus was intended to be issued as the central pedagogical work against slavery. Two other bulls would be published to implement the teaching of Sublimis, one to impose penalties on those who fail to abide by the teaching against slavery, and a second to specify the sacramental consequences of the teaching that the Indians are true men.
The first central teaching of this beautiful work is the universality of the call to receive the Faith and salvation:
"And since mankind, according to the witness of Sacred Scripture, was created for eternal life and happiness, and since no one is able to attain this eternal life and happiness except through faith in our Lord Jesus Christ, it is necessary to confess that man is of such a nature and condition that he is capable to receive faith in Christ and that everyone who possesses human nature is apt for receiving such faith . . . Therefore the Truth Himself Who can neither deceive nor be deceived, when He destined the preachers of the faith to the office of preaching, is known to have said: 'Going, make disciples of all nations.' 'All,' he said, without any exception, since all are capable of the discipline of the faith."
The teaching of Sublimis continued:
"Seeing this and envying it, the enemy of the human race, who always opposes all good men so that the race may perish, has thought up a way, unheard of before now, by which he might impede the saving word of God from being preached to the nations. He has stirred up some of his allies who, desiring to satisfy their own avarice, are presuming to assert far and wide that the Indians of the West and the South who have come to our notice in these times be reduced to our service like brute animals, under the pretext that they are lacking the Catholic Faith. And they reduce them to slavery (Et eos in servitutem redigunt), treating them with afflictions they would scarcely use with brute animals."
The common pretext of the allies of "the enemy of the human race," i.e. Satan, for enslaving the Indians was that they lacked the Faith. Some of the Europeans used the reasoning that converting the Indians should be accomplished by any means necessary, thus making the Faith an excuse for war and enslavement. Paul III stated that the practice of this form of servitude was "unheard of before now." This clearly indicates that the practice of enslaving an entire ethnic group of people - the Indians of South America-for no morally justifiable reason was indeed different from anything previously encountered.
The second core teaching of Sublimis Deus which follows from this is the necessity of restoring and maintaining the liberty of the Indians:
"Therefore, We, . . . noting that the Indians themselves indeed are true men and are not only capable of the Christian faith, but, as has been made known to us, promptly hasten to the faith' and wishing to provide suitable remedies for them, by our Apostolic Authority decree and declare by these present letters that the same Indians and all other peoples-even though they are outside the faith-who shall hereafter come to the knowledge of Christians have not been deprived or should not be deprived of their liberty or of their possessions. Rather they are to be able to use and enjoy this liberty and this ownership of property freely and licitly, and are not to be reduced to slavery, and that whatever happens to the contrary is to be considered null and void. These same Indians and other peoples are to be invited to the said faith in Christ by preaching and the example of a good life."
Thus, we see that Eugene IV and Paul III did not hesitate to condemn the forced servitude of Blacks and Indians, and they did so once such practices became known to the Holy See. Their teaching was continued by Gregory XIV in 1591 and by Urban VIII in 1639. Indeed Urban, in his document Commissum Nobis, appealed to the teaching of his predecessors, particularly Paul III. The pontifical teaching was continued by the response of the Holy Office on March 20, 1686, under Innocent XI, and by the encyclical of Benedict XIV, Immensa Pastorum, on December 20, 1741. This work was followed by the efforts of Pius VII at the Congress of Vienna in 1815 to have the victors over Napoleon outlaw slavery.