Thus, the 1455 Papal Bull Romanus Pontifex granted the Portuguese all lands behind Cape Bojador and allowed them to reduce pagans and other "enemies of Christ" to perpetual slavery.
Bartolomé de Las Casas, author of A Short Account of the Destruction of the Indies, championed the cause of the natives, and was opposed by Sepúlveda, who claimed Amerindians were "natural slaves".
However, while the School of Salamanca limited Charles V's imperial powers over colonized people, they also legitimized the conquest, defining the conditions of "Just War".
For example, these theologians admitted the existence of the right for indigenous people to reject religious conversion, which was a novelty for Western philosophical thought.
Hence, war was justified if the indigenous people refused free transit and commerce to the Europeans; if they forced converts to return to idolatry; if there come to be a sufficient number of Christians in the newly discovered land that they wish to receive from the Pope a Christian government; if the indigenous people lacked just laws, magistrates, agricultural techniques, etc.
Henceforth, the School of Salamanca legitimized the conquest while at the same time limiting the absolute power of the sovereign, which was celebrated in others parts of Europe under the notion of the divine right of kings.
Aspects of it were officially criticised in 1984 and in 1986 by then Cardinal Ratzinger (later Pope Benedict XVI) as the head of the Congregation for the Doctrine of the Faith, under charges of Marxist tendencies, who nevertheless praised its commitment to social justice, poverty and what he called the 'scandal of the arms race'.
Whereas Spanish colonialism was based on the religious conversion and exploitation of local populations via encomiendas (many Spaniards emigrated to the Americas to elevate their social status, and were not interested in manual labour), Northern European colonialism was frequently bolstered by people fleeing religious persecution or intolerance (for example, the Mayflower voyage).
The motive for emigration was not to become an aristocrat nor to spread one's faith but to start afresh in a new society, where life would be hard but one would be free to exercise one's religious beliefs.
However, the English, French and Dutch were no more averse to making a profit than the Spanish and Portuguese, and whilst their areas of settlement in the Americas proved to be devoid of the precious metals found by the Spanish, trade in other commodities and products that could be sold at massive profit in Europe provided another reason for crossing the Atlantic, in particular furs from Canada, tobacco and cotton grown in Virginia and sugar in the islands of the Caribbean and Brazil.
The islands of the Caribbean soon came to be populated by slaves of African descent, ruled over by a white minority of plantation owners interested in making a fortune and then returning to their home country to spend it.
January 27, 1512 Leyes de Burgos codified the government of the indigenous people of the New World, since the common law of Spain wasn't applied in these recently discovered territories.
The document finally prohibited the use of any form of punishment by the encomenderos, reserving it for officials established in each town for the implementation of the laws.
Ten years later, Dominican friar Bartolomé de las Casas would publish A Short Account of the Destruction of the Indies, in the midst of the Valladolid Controversy.
"Even if these figures are remotely true", writes Rummel, "then this still make this subjugation of the Americas one of the bloodier, centuries long, democides in world history.
The Portuguese and Spanish use of slavery in Latin America was seen as a lucrative business which ultimately led to internal and external development in gaining economic influence at any cost.
Pérez and his men conducted slave trading in which thousands of African peoples were bought from local tribal leaders and transported across the Atlantic to South America.
Furthermore, local tribal leaders did not simply give up their own people for the aforementioned commodities but rather through intertribal wars, debts, and civil crime offenders.
According to David Eltis, areas controlled by the Spanish such as Mexico, Peru, and large parts of Central America used forced slave labor in "mining activities".
[8] Many African people died in large numbers in order to meet the demand for Spanish and Portuguese labor requirements.
The lucrative business the Portuguese sought on the West African coast ushered in an era in which human labor, at any cost, was used for the extraction of wealth.