Sapa Inca succession did not follow strict primogeniture; a reigning Inca typically selected a successor from among his sons, weighing personal capability alongside the status of the candidate's mother, ideally the Coya, the Sapa Inca's principal wife who was, in the empire's later ideology, also frequently his own sister. Because the choice was not automatic, succession could produce serious conflict among royal brothers, most consequentially the civil war between Huascar and Atahualpa in the years immediately before the Spanish arrival, a war that had already fractured the empire's unity and military strength when Francisco Pizarro's expedition landed in 1532.
Atahualpa, having just defeated Huascar, was captured by Pizarro at Cajamarca later that year; the Spanish accepted an enormous ransom in gold and silver for his release and then executed him regardless in 1533, formally ending independent Inca rule at Cuzco. Resistance continued for decades under a rival line of Sapa Incas at Vilcabamba, a remote jungle refuge state, until Spanish forces captured and executed the last of them, Tupac Amaru, in 1572, an event generally treated as the final end of the Inca imperial office, though the Sapa Inca title and Inca noble lineages continued to carry social significance in colonial Peru for generations afterward.