The Paraguayan War also known as War of the Triple Alliance (Spanish: Guerra de la Triple Alianza; Portuguese: Guerra da Tríplice Aliança), was a military conflict

War

War is a state of organized, armed, and often prolonged conflict carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political...

 in South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 fought from 1864 to 1870 between Paraguay

Paraguay

Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...

 and the Triple Alliance

Treaty of the Triple Alliance

The Treaty of the Triple Alliance was a treaty which allied Brazil, Argentina, and Uruguay in the Paraguayan War. Signed at the beginning of the war, its articles prescribed the allies' actions both during and after the war.- Legal Restrictions :...

 of Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

, Brazil, and Uruguay

Uruguay

Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...

. It caused more deaths proportionally than any other war in modern history

Modern history

Modern history, or the modern era, describes the historical timeline after the Middle Ages. Modern history can be further broken down into the early modern period and the late modern period after the French Revolution and the Industrial Revolution...

, and particularly devastated Paraguay, killing most of its male population.

Several theories exist regarding the origins of the war.