The Spanish conquistador Pizarro and his men were greatly aided in their enterprise by invading when the Inca Empire was in the midst of a war of succession between the princes Huáscar and Atahualpa. Atahualpa seems to have spent more time with Huayna Capac during the years when he was in the north with the army conquering Ecuador. Atahualpa was thus closer to and had better relations with the army and its leading generals. When both Huayna Capac and his eldest son and designated heir, Ninan Cuyochic, died suddenly in 1528 from what was probably smallpox, a disease introduced by the Spanish into the Americas, the question of who would succeed as emperor was thrown open. Huayna had died before he could nominate the new heir.