The Paraguayan War, also known as the War of the Triple Alliance, was an international military conflict in South America fought from 1864 to 1870 between Paraguay and the Triple Alliance of Argentina, Brazil, and Uruguay. It is said to have caused approximately 400,000 deaths, one of the highest ratios of fatalities to combatants of any war in South America in modern history. It was the longest and bloodiest inter-state war in Latin American history. It particularly devastated Paraguay, which suffered catastrophic losses in population—some claim that almost 70% of its adult male population died—and was forced to cede territory to Argentina and Brazil.