The Paraguayan War, also known as the War of the Triple Alliance, was a conflict between a coalition consisting of the Brazilian Empire, Uruguay, and Argentina, against Paraguay. The coalition sought to overthrow the Paraguayan government and to seize certain Paraguayan territories. Paraguay sought to increase its military might and influence in South America. In 1870, the allied troops managed to take Asunción, which ended the war. The allies lost about 120,000 men, while Paraguay suffered 280,000 deaths, corresponding to more than half of its population.

The war is known as the bloodiest conflict in Latin American history. Paraguay had for years been faced with disputes over boundaries and tariffs with Argentina and Brazil, struggling to safeguard their independence. When the war was over, Argentina and Brazil annexed about 140,000 square kilometres of Paraguayan territory while also demanding a large indemnity and occupying Paraguay until 1876.