A detailed analysis of the references about Inca successions confirms that in the Andean sphere primogeniture, so generalized in the Old World, did not exist and therefore bastardy was not a consideration either.

The existing tradition in the Andes designated for succession to power the right of the "most skilful" of the candidates. Naturally, the custom generated intrigues, battles and death at the demise of every sovereign and with regard to the necessity of effecting a change in government. Moreover, the Inca possessed numerous wives and among them was distinguished the coya or queen with whom he married the day he received the tassel, the insignia of power.

The inheritances became so tempestuous that an attempt was made to take certain measures to remedy the uproar that was produced. Thus came about that the Inca made the election of his successor, or rather of a co-regente who received the tassel and a new wife the day he was named. Unfortunately the candidate could not be revoked if he did not demonstrate he possessed the necessary requisites for being a governor. That is how three Incas of singular capacity succeeded each other as did Pachacutec, Tupac Yupanqui and Huayna Capac.

Nevertheless, Huayna Capac despite his advanced age did not name a co-regent. His death, caused by the epidemics which decimated the indigenous population and thedeath of successor he designated, caused confusion among between the priests entrusted with the succession.

In view of this void, Huascar, sustained by his mother Raura Ocllo, and Atahualpa, the favorite of the army, competed for the power to find out which of the two would triumph and turn into the "most able". There is no lack of historians who see decadence in the fratricidal fight or blame the war on the enormous territorial extension acquired by the State. However, the situation of conflict was produced throughout the Inca state, inconclusive, coming to the suppression of elected sovereigns such as Tarco Huaman, which brought as a consequence internecine battles and seraglio intrigues such as happened at the death of Tupac Yupanqui. His marriage with a "sister", another way of consolidating the right to an aspirant with a tassel, was not worth anything.

The case of Amaru Yupanqui, a revoked appointment

After long years of government, Pachacutec named as co-regent his son called Amaru Yupanqui. However, the prince did not show himself to be a warrior since, being of a gentle nature, he preferred to busy himself with agriculture and cultivating his own lands.

A chronicler recounts that during a long drought, the only green fields were Amaru Yupanqui's due to the hydraulic canals he constructed which carried the needed water to his fields. But the State needed a warrior prince and Pachacutec revoked the appointment of Amaru and designated another son of his called Tupac Yupanqui, who was a great conqueror.

Although placid Amaru remained excused from power he did not stop having a high rank in the government and kept his lands and his palace. One of his tasks was that of visiting the sanctuaries and the huacas of Collasuyu in the company of a brother.

The co-regent Tupac Yupanqui, on receiving the tassel married a "sister", not necessarily by both mother and father. The Cuzco governors tried by this means to reduce the number of battles for power and sought the support of maternal rights or the influence of the mother on the election of a candidate.