Cristóbal de Olid in the context of Diego Velázquez de Cuéllar

Indian auxiliaries, also known in the sources as Indios amigos (lit. 'friendly Indians'), were those Indigenous peoples of the Americas who allied with Spain and fought alongside the conquistadors during the Spanish colonization of the Americas. These auxiliaries acted as guides, translators, soldiers, explorers and porters, often outnumbering peninsular Spaniards by enormous degrees in their military formations. During the Spanish conquest of the Inca Empire, Indigenous assistants were referred to by the Indigenous word of yanakuna.

Indian auxiliaries continued to be used by the Spanish to maintain control over their colonies in the Americas; frequently stationed on the frontier, they were often used to suppress anti-colonial revolts such as Arauco War. Their important role in achieving the conquests of Spain gave birth to a modern Spanish-speaking idiom, la conquista la hicieron los indios ("the Indians did the conquest").