What was the Paraguayan War?

How it started

The war grew out of a civil war in Uruguay, where Brazil and Paraguay backed opposite sides. The events, in order:

1. 1864: Brazil intervenes in Uruguay’s civil war to put an ally in power. Paraguay’s president, Francisco Solano López, backs the other side.
2. November 1864: Paraguay seizes the Brazilian steamer Marquês de Olinda on the Paraguay River, with the governor of the Brazilian province of Mato Grosso on board.
3. December 1864: Paraguayan troops invade Mato Grosso.
4. April 1865: on their way to Uruguay, Paraguayan forces cross into Argentina at Corrientes.
5. May 1, 1865: Brazil, Argentina and Uruguay’s new government sign the Treaty of the Triple Alliance.

Everyone expected a war of a few months. It lasted more than five years.

Riachuelo, Tuiuti and Humaitá

Paraguay has no coast, so the rivers were the roads of the war. On June 11, 1865, on the Paraná River near Corrientes, Admiral Francisco Manuel Barroso’s squadron met Paraguay’s at the Battle of Riachuelo. A signal went up the mast of his ship, the Amazonas: “Brazil expects every man to do his duty,” an echo of Nelson’s signal at Trafalgar. Barroso rammed the enemy, and the allies took control of the rivers. June 11 is still the Brazilian Navy’s great day.

On land the war turned into slaughter. On May 24, 1866, at Tuiuti, in a swamp in southern Paraguay, came the largest pitched battle ever fought in South America; thousands of Paraguayans died in a few hours. Four months later, at Curupaiti, a frontal allied assault ended in a massacre. The Empire then called on Caxias, the general who had pacified Brazil’s south. He reorganized the army, used observation balloons to spy on the enemy and besieged the fortress of Humaitá, which fell in 1868. In January 1869 Brazilian troops entered Asunción.

Volunteers and the enslaved

Brazil’s imperial army was small, about 18,000 men. In January 1865 a decree created the Voluntários da Pátria, the Volunteers of the Fatherland:

Extraordinary corps are hereby created for war service, made up of all citizens over eighteen and under fifty years of age who wish to enlist voluntarily.

The enthusiasm did not last, and forced recruitment followed. At least 6,000 enslaved men were freed to fight, many of them sent in place of their masters’ sons.

Why it ended only with López’s death

The Treaty of the Triple Alliance bound the allies not to lay down their arms until López’s government had fallen. So the war went on after Asunción, deep into the interior. In the end Paraguay was fighting with old men and boys, and on March 1, 1870, López was killed at Cerro Corá. The human cost, and why the estimates differ so much, is in How many people died in the Paraguayan War?

Brazil won, but came out deep in debt to London banks, and its army came home with prestige and a grudge against the politicians, one of the roots of the fall of the monarchy under Pedro II. The war also left its names on the map: streets called Voluntários da Pátria and Riachuelo in many Brazilian cities, and the slang “caxias” for anyone who goes strictly by the book, after the general who became the army’s patron.