Alejo (1635 – 1660) was a Chilean mestizo, who fought in the Arauco War. He was the son of the Mapuche cacique Curivilú and the Spanish Isabel de Vivar y Castro who was captured during a Mapuche raid. Isabel and Alejo were rescued five years later and rejoined the Spanish society. Alejo enlisted the Spanish army, but the system of castas prevented his promotion. As a result, he deserted from the Spanish army and joined the Mapuches, being appointed toqui. Instructed in Spanish military strategy, he posed a serious threat to his former masters, but he died in a crime of passion: after he had sex with a captured Spanish woman his two wives murdered him.