Shortly after reaching America in the 15th century, Spanish explorers learned of the riches of the Incas, and in 1524 Francisco Pizarro sailed from Panama in his first attempt to reach the Inca homeland. It was unsuccessful. In 1527, on his second voyage, he reached Tumbes, on the south shore of the Gulf of Guayaquil. In May, 1532, Pizarro returned with a force of 180 men to Tumbes. There he learned that the death of the Inca emperor, Huayna Capac, had led to civil war between his sons Atahualpa and Huáscar. The victorious Atahualpa was camped across the Andes Mountains at Cajamarca. Pizarro marched his forces over the mountains and by treachery took Atahualpa prisoner. Atahualpa was forced to pay an immense ransom, and was then put to death. Inca resistance collapsed, and Cuzco was occupied in the autumn of 1533. A new capital, Lima, was built, with Callao as its port.

Diego de Almagro, a close associate of Pizarro's, was made governor of a region to the south (Chile and southern Bolivia). Finding no riches there and feeling cheated, Almagro seized Cuzco from Pizarro's forces. Pizarro retook the city and put Almagro to death in 1538. In 1541 Pizarro was slain by Almagro's followers. To establish order Charles I of Spain sent a viceroy, who was deposed in 1548 by Gonzalo Pizarro, Francisco's half brother, who had earlier declared himself governor. Royal authority was established in 1548.