In the event of failure of sons by the legitimate wife, it was lawful for the eldest relation of pure blood to inherit (as Manco Ynca succeeded Huascar, as will be recorded in its place), and so on with the rest, but under no circumstances could a bastard be allowed to inherit, and when there was no legitimate son of pure blood, the succession went to the nearest legitimate male relation.

It was on account of this law that Atahualpe destroyed the whole royal family, both men and women, as we shall relate in its place, because he was a bastard, and feared that the kingdom might be taken from him, and given to one who was legitimate. All those of the blood royal married with their relations to the fourth degree, for they had many legitimate children. But they reserved the daughter, whose marriage to a brother was only permitted in the case of the king. The eldest son always inherited the kingdom, and this mode of succession never failed in the twelve generations that reigned down to the time of the Spaniards. Amongst the Curacas, who were lords of vassals, there were various customs respecting the inheritance of estates. In some provinces the eldest son inherited, the succession going regularly from father to son. In others, the son inherited who was most popular with the vassals, on account of his virtue or affability, which was more like an election than an inheritance.