Río Biobío
In 1550 Pedro de Valdivia, who aimed to control all of Chile to the Straits of Magellan, traveled southward to conquer Mapuche territory. Between 1550 and 1553 the Spanish founded several cities in Mapuche lands including Concepción, Valdivia, Imperial, Villarrica and Angol. The Spanish also established the forts of Arauco, Purén and Tucapel. The key areas of conflict that the Spanish attempted to secure south of Bío Bío River were the valleys around Cordillera de Nahuelbuta. The Spanish designs for this region were to exploit the placer deposits of gold using unpaid Mapuche labour from the densely populated valleys.