Peru and Chile sign the Treaty of Ancón, by which the Tarapacá province is ceded to the latter, bringing an end to Peru's involvement in the War of the Pacific.

The Treaty of Ancn was signed by Chile and Peru on 20 October 1883, in the Ancn District near Lima. It was intended to settle the two nations' remaining territorial differences at the conclusion of their involvement in the War of the Pacific and to stabilise post-bellum relations between them.

Under the treaty's terms, Chile gained control over Tarapac. Chile was also to retain the conquered provinces of Tacna and Arica for ten years, after which their fate was to be decided by a plebiscite. The plebiscite was never held.Finally, in 1929, through the mediation of the United States under President Herbert Hoover, an accord was reached. Under the Tacna-Arica compromise, Chile kept Arica, while Peru regained Tacna and received USD $6 million indemnity and other concessions.Another important provision in the treaty said that Chile could not cede sovereignty of former Peruvian territories to other nations without asking Peru first. The Chapter has been invoked once, during the Chilean proposal of 1975 that offered Bolivia sovereignty over some minor ports. The Peruvian government rejected the proposed land swap.

Peru ( (listen); Spanish: Perú [peˈɾu]; Quechua: Piruw [pɪɾʊw]; Aymara: Piruw [pɪɾʊw]), officially the Republic of Peru (Spanish: República del Perú ), is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pacific Ocean. Peru is a megadiverse country with habitats ranging from the arid plains of the Pacific coastal region in the west to the peaks of the Andes mountains extending from the north to the southeast of the country to the tropical Amazon Basin rainforest in the east with the Amazon river. Peru has a population of 34 million, and its capital and largest city is Lima. At 1.28 million km2 (0.5 million mi2), Peru is the 19th largest country in the world, and the third largest in South America.

Peruvian territory was home to several ancient cultures. Ranging from the Norte Chico civilization starting in 3500 BCE, the oldest civilization in the Americas and one of the five cradles of civilization, to the Inca Empire, the largest known state in the pre-Columbian Americas, the territory now including Peru has one of the longest histories of civilization of any country, tracing its heritage back to the 10th millennium BCE.

The Spanish Empire conquered the region in the 16th century and established a viceroyalty that encompassed most of its South American territories, with its capital in Lima. Higher education started in the Americas with the official establishment of the National University of San Marcos in Lima in 1551. Peru formally proclaimed independence in 1821, and following the foreign military campaigns of José de San Martín and Simón Bolívar, and the decisive battle of Ayacucho, Peru completed its independence in 1824. In the ensuing years, the country first suffered of political instability until a period of relative economic and political stability begun due to the exploitation of guano. Later, the War of the Pacific (1879–1884) with Chile brought Peru to a state of crisis from which the oligarchy seized power through the Civilista Party. In the 20th century, the country endured coups, social unrest, and internal conflicts, as well as periods of stability and economic upswing. In the 1990s, the country implemented a neoliberal economic model which is still in use to this day. As the 2000s commodities boom took place, Peru experienced a period of constant economic growth and a decrease in poverty.

The sovereign state of Peru is a representative democratic republic divided into 25 regions. Peru has a high level of human development with an upper middle income level ranking 82nd on the Human Development Index. It is one of the region's most prosperous economies with an average growth rate of 5.9% and it has one of the world's fastest industrial growth rates at an average of 9.6%. Its main economic activities include mining, manufacturing, agriculture and fishing, along with other growing sectors such as telecommunications and biotechnology. The country forms part of The Pacific Pumas, a political and economic grouping of countries along Latin America's Pacific coast that share common trends of positive growth, stable macroeconomic foundations, improved governance and an openness to global integration. Peru ranks high in social freedom; it is an active member of the Asia-Pacific Economic Cooperation, the Pacific Alliance, the Trans-Pacific Partnership and the World Trade Organization; and is considered as a middle power.Peru has a population that includes Mestizos, Amerindians, Europeans, Africans and Asians. The main spoken language is Spanish, although a significant number of Peruvians speak Quechua languages, Aymara, or other Indigenous languages. This mixture of cultural traditions has resulted in a wide diversity of expressions in fields such as art, cuisine, literature, and music.