He was involved in the fighting struggle between the Incas and the Chankas (of modern-day Apurímac, west of Cusco). The chroniclers differ on whether he was a hero or a coward. According to some, such as Inca Garcilaso de la Vega, his father Yawar Waqaq abandoned the capital under the attack of the Chankas; Viracocha defeated the enemy and saved the city. Others, such as Pedro Cieza de León and Juan de Betanzos, claim that Viracocha abandoned the city and that his son Pachacuti saved it.
One chronicler, Sarmiento de Gamboa, states that Viracocha was the first Incan to rule the territories he conquered, while his predecessors merely raided and looted them.