In 1532, Spanish conquistadors under Francisco Pizarro first made contact with the mighty Inca Empire that ruled parts of present-day Peru, Ecuador, Chile, Bolivia and Colombia. Within 20 years, the Empire was in ruins and the Spanish were in undisputed possession of the Inca cities and wealth.
The Inca Empire had been collecting gold and silver for centuries and the Spanish soon found most of it. A great amount of gold was even hand-delivered to the Spanish as part of Atahualpa’s ransom.
The long-term effects of the arrival of the Spanish on the population of South America were simply catastrophic.
While this is the case for every group of Native-Americans that encountered Europeans from the fifteenth century onwards, the Incan population suffered a dramatic and quick decline following contact with the Spaniards.
The single greatest cause of death of the Incas by far was disease. Old World diseases like Smallpox and Measles brought over unknowingly by colonists and conquistadors wreaked havoc on native populations at a greater rate than any army or armed conflict.
The fact that the Inca did not have as strong of a writing tradition as the Aztecs or Maya is one reason why it is more difficult to estimate population decline or any events after conquest.
Beyond the devastation of the local populations by disease, there was also considerable enslavement, pillaging and destruction from warfare. Thousands of women were taken from the local populations by the Spanish and used by conquistadors as personal slaves.
Another significant effect on the people in South America was the spread of Christianity. As Pizarro and the Spanish subdued the continent and brought it under their control, they forcefully converted many to Christianity, claiming to have educated them in the ways of the “one true religion.” With the depopulation of the local populations along with the capitulation of the Inca Empire, the Spanish missionary work after colonization began was able to continue unimpeded. It took just a generation for the entire continent to be under Christian influence and eradication of their culture.