Why did Spanish and Portuguese begin using African slaves in their new world colonies in the 1500s

The slavery in America includes the enslavement of part of the indigenous population from the discovery of America and the subsequent importation to America of slaves captured in sub-Saharan Africa.

After the discovery of America in 1492 by the Spaniards, the transportation of blacks from Arguin to Santo Tomé and San Jorge de la Mina and the Cape Verde islands increased enormously due to the demand of thousands of slaves. This became a big business for latifundistas, merchants, slavers and European kings.

The king of Portugal derived benefits from this through the House of Slaves, with the seat of the black out of the factories, and the Spanish monarchs made profits to cost to sell licenses to allow black slaves to America. The license to transport a slave cost 8 ducats and in the 16th century more than 120,000 licenses were granted in Spain.

As in many areas of America there were not many Indians left because of the epidemics, but the demand for labor continued to grow, the Spaniards began to import African slaves. Even the friar Bartolomé de las Casas recommended the importation of Africans to eliminate the shortage,

The slaves were used habitually in the haciendas and obrajes as well as in the American mining. The first slaves were requested by the Franciscan friars and the Royal Audience of Santo Domingo to work on the plantations. Then they were requested by Mexico, Peru and the Río de la Plata.