Almagro, Diego de (1475?–1538), a Spanish soldier and explorer. During 1524–33, Almagro helped Francisco Pinzarro overthrow the Inca empire of Peru. He was given none of the conquered lands, receiving instead territory to the south (now Chile and southern Bolivia), In 1535 Almagro led an expedition to this area. When he found only hostile Indians and no gold, he was enraged and began a war with Pizarro. Almagro was captured and put to death.