A country of western South America on the Pacific Ocean. Inhabited since at least the 9th millennium bc , it was the center of the Inca Empire after the 12th century ad . Francisco Pizarro's conquest of the Inca in 1533 led to the establishment in 1542 of the Spanish viceroyalty of Peru, which in time included Panama and all of Spanish South America except Venezuela. Peru achieved full independence from Spain in 1824. Lima is the capital and the largest city.