About a quarter of the toponymy in Elqui Valley is of indigenous origin, overwhelmingly Quechua and Mapuche.[4] There is scant Diaguita (Kakan) toponyy known in the area despite it being considered a homeland of that people by various authors.[4] Quechua toponymy is related to valleys incorporation to the Inca Empire in the late 15th and early 16th-century. Some Mapuche toponymy posdates Inca rule, but other may be coeval or even precede it.[4] Toponyms recognised as Nahua, Kunza, Diaguita, Aymara and Taino make together up less than 10% of the all placenames in Elqui Valley.[4]
It is generally accepted that incorporation of north-central Chile to the Inca Empire was through warfare which caused a severe depopulation in the Transverse Valleys of Norte Chico, the wider Diaguita homeland.[5] Chilean toponymy in Tarija, Bolivia, including "Erqui" along with other evidence have been interpreted to suggest that Incas deported defeated tribes from Elqui Valley to southern Bolivia.[6][7] After or during conquest Incas would have settled foreign tribes in Elqui Valley,[7] and ended up imposing Quechua placenames on the local geography.[4] There is uncertainty about the date of these transfers.[4][7] Chronicler Diego de Rosales tells of an anti-Inca rebellion in the Diaguita lands of Coquimbo and Copiapó concurrent with the Inca Civil War.[8] This rebellion would have been brutally repressed by the Incas who gave rebels "great chastise".[8]
