The Inca (also Inka) Empire, called by the Andeans themselves “Tawantinsuyu,” referred to its four parts: the Chinchaysuyu, the Antisuyu, the Collasuyu, and the Cuntisuyu. Inter-disciplinary research pictures an assemblage of ethnic groups under a dynasty of rulers, believed to have supernatural origins. This multi-cultural state, overseen by a decimally-defined administrative system, was united by kinship ties; the worship of the sun, the moon and ethnic ancestors; negotiation; reciprocity; and force. At its height, it spread from Northwestern Argentina, through Bolivia, Peru, and Ecuador, and included about half of Chile and the southern frontier of Colombia. Troubles began in the 1520s as a strange disease decimated the native population, claiming the emperor himself. Yet, the Inca’s jurisdiction continued to expand until circa 1532, the date when Francisco Pizarro and his followers and allies marched across the Andes and confronted the Andean emperor Atahualpa in the plaza of the highland ceremonial center of Cajamarca.