The Spanish conquest of the Inca Empire was one of the most important campaigns in the Spanish colonization of the Americas. After years of preliminary exploration and military skirmishes, 168 Spanish soldiers under Francisco Pizarro and their native allies captured the Sapa Inca Atahualpa in the 1532 Battle of Cajamarca. It was the first step in a long campaign that took decades of fighting but ended in Spanish victory in 1572 and colonization of the region as the Viceroyalty of Peru. The conquest of the Inca Empire led to spin-off campaigns into present-day Chile and Colombia, as well as expeditions towards the Amazon Basin.