The first attempt to explore western South America was undertaken in 1522 by Pascual de Andagoya. The native South Americans he encountered told him about a gold-rich territory called Virú, which was on a river called Pirú (later corrupted to Perú) and from which they came. These reports were related by the Spanish-Inca mestizo writer Garcilaso de la Vega in his famous Comentarios Reales de los Incas (1609).