How did the Spanish conquest affect Native Americans and Africans? Native Americans were forced to work on haciendas and in mines. Many died from overwork, malnutrition, and disease. The Spanish then brought millions of enslaved Africans to work in the Americas. During the 1500’s, Native Americans and Africans led many successful rebellions. The population of Native Americans and Africans increased. The land owned by Native Americans increased. To meet the labor demands, they brought millions of enslaved Africans to work in the Americas.