The present population of South America is the result of four centuries of mixture among these four components—American Indians, Iberians, Africans, and more recent overseas immigrants—and their descendants. The mixing process began when the first Iberians reached South America. The previous traditions and basic values and attitudes of the Iberians—coupled with other characteristics of their conquest and colonization—facilitated intermixing not only with the Indians but in general among all the various ethnic groups, although the intensity, extent, and frequency of this mixing varied both among different groups and at different times.

Legal marriage between Iberians and Indians was tolerated, often permitted, and even, in some special circumstances, promoted. It was possible—and in certain epochs easy—to recognize mestizo (generally, mixed European and Indian) children, though frequently a mestizo was considered automatically illegitimate.