The Inca Civil War was a devastating conflict that occurred in the early 16th century between rival factions of the Inca Empire, primarily between the brothers Atahualpa and Huáscar, as they vied for control of the empire following the death of their father, Huayna Capac. This internal struggle significantly weakened the Inca state, making it vulnerable to Spanish conquest and altering the balance of power in the Andean region.