There is a big question about the true intentions of Spanish policy towards indigenous peoples, as they claimed that their main intention was to add the continent of South America under the rule of the Spanish Crown, which would mean that they would be subjects of Spain. Therefore, it would be against the law to force them into slavery. But the chronist Bartolome de las Casas wrote a series of texts denouncing the treatment that the inhabitants of this new Spanish colony suffered. He was a friar of the Dominican order and defended that those who had converted to Christianism and became Christians were under the protection of the Roman Catholic Church. Spain's Catholic monarchs, King Ferdinand II of Aragon and Queen Isabella I of Castile had little enthusiasm for slavery and, as a result, the Crown opposed to Columbus' scheme to turn the Caribbean territories into a prosperous slave trade for Spain and he was imprisoned for a short time. Queen Isabella I, tried to improve the situation by establishing a system of indentured landholding, sought to strengthen the situation for the Native Americans, whereby the Indians were, in principle, to farm the land of the Spaniards four days a week with the rest of the week to take care of their own portions of land - the well-known corvee system in feudal Western Europe. Nonetheless, the local Spaniards in the Spanish colonies in the New World did everything in practice on the ground to effectively prevent any limitations on their realistic ability to exploit the natives. The Queen died in 1504, and her wish was for the Indians to be treated well and equally, but her husband, King Ferdinand II, exercised the Crown's right to enslave the Indians, and their condition deteriorated after 1504.
The situation improved with the arrival of Charles of Hasburg the I King of Spain, and V Emperor of Germany, who expressly ordered the abolition of slavery among the native Indians in 1530, followed by the creation of the New Laws of the Indies the 20th of November 1542 as a new compilation of anti-slavery laws in the Spanish colonies. Furthermore, in his 1537 Papal Bull, Pope Paul III had proclaimed the Indians to be true human beings and, thus, deserving of obtaining the Christian faith. Therefore, Native Americans should not be stripped of their liberty and property ownership under the eyes of God. However, the peak of the demographic tragedy of the native inhabitants of the Spanish colonies had already arisen and, as a consequence from the Spaniards bringing black slaves from Portuguese Africa to the New World to do the harsh physical labor that the Native Americans had previously performed in the first half of the 16th century had a striking impact. Soon, the numbers of black Africans quickly exceeded the numbers of their Spanish masters, but the Spanish colonial governors and their leaders continued to practice the brutal abuse of both the indigenous people of the Americas and the newly brought slaves from Africa. This derived into the creation of the caste system.
Before arriving in America, Spanish society used the concept of caste to distinguish 'old Christians' from 'new Christians', converted Jews and Muslims. Upon arriving in America, this changed, and they associated it with miscegenation. The social groups of New Spain and South America were made up of Spanish whites who, as the dominant elite, occupied the vertex of the social pyramid. Behind them were the white Creoles - sons of Spaniards born in America; the indigenous - original inhabitants of the continent; and the black population - slaves brought from Africa. From the interrelation between all of them, a particularly complex new broad group would emerge: the mestizos. In an interracial society dominated by Spaniards but with little presence of Spanish women, miscegenation was favored and was soon justified under the ideological principle of cleansing and blood whitening. It was believed that the mixing of whites with indigenous people could eventually result in the formation of a 'white' offspring. Black people were excluded from this belief, and they were held responsible for 'staining' the race. Hence, the hierarchy of castes was defined by virtue of the degree of Spanish blood, by virtue of the 'purity' of the descendants of interracial unions. The higher the purity - Spanish blood, the more rights; to a lesser degree, reduced duties. Thus, the colonial caste system was generated. This affected social positions and status, meaning by this than the lower the position, the harder the work and the living conditions.
Even though slavery was punished by law, the creation of the caste system became its successor regarding the priorities and opportunities offered to the subjects of the Spanish Crown in Latin America. It can be argued that the mixture of race and ethnicity portrays the idea of the Spaniards of making the native people of Latin America their subjects instead of their eradication.