Bolivian history emerges from the realm of conjecture with the invasion of the Incas, a warlike and civilised tribe who inhabited the slightly lower plateaux and valleys north-east of the Titicaca basin. The ancient Titicacan civilisation had long since fallen from its high estate and the Inca armies easily overcame the resistance of the scattered shepherd tribes. The conquered aborigines were incorporated with the Incas and Quichua became the principal although not the only language. Great colonies of the dominant race spread south and east over the massif into the fertile regions of Yungas, Cochabamba, and Charcas. Bolivia became one of the principal seats of the Inca power. There they built their most magnificent palaces; in the northern mountains they found the copper for their tools and weapons, and the gold which they used to ornament their temples. Over the higher plains roamed flocks of llamas and vicunas. The slightly lower parts of the plateau produced potatoes and quinoa, and the warmer valleys maize, cocoa, and cotton. The broad lake, the rivers, and the roads over the comparatively level country favoured intercommunication and social and industrial consolidation. In the terrible civil war which broke out about 1525 between Atahuallpa and Huascar, Bolivia suffered less than the Peruvian and Ecuadorean provinces, but thousands of her sons were drafted into the armies which Huascar successively launched against Quizquiz and the horde of northern tribes which relentlessly marched from Quito to Cuzco, and after five years of slaughter captured the southern capital and the legitimate emperor. But before Quizquiz had had time to pursue his conquering way into Bolivia, news came that Pizarro had imprisoned and murdered Atahuallpa, and that the Spaniards were on their way to Cuzco to give battle to Quizquiz and restore the legitimate succession. The northern Indians were defeated and at the close of 1533 Pizarro entered Cuzco in triumph riding at the side of Huascar's heir. The people of southern Peru, Bolivia, Tucuman, and Chile regarded the Spaniards as deliverers and allies. Within a few months after the occupation of Cuzco the strangers rode out of the city along the splendid stone-flagged Inca roads, crossed the transverse range into the Titicaca basin, and followed south-east to the extremity of the plateau, encountering little resistance and regarded as ambassadors from the Inca emperor. They found the country teeming with a docile and prosperous population, and the mountains on its borders were reported to abound in silver, gold, and copper. Almagro, Pizarro's partner and associate, to whose share had fallen the southern half of the empire, resolved not only to take possession of Bolivia, but also to conquer the great province which the Indians told him lay far to the south in fertile valleys on the western side of the Andes and hard by the Pacific Ocean.