The Paraguayan War (1864–1870)
The deadliest interstate war in Latin American history, fought between Paraguay and the Triple Alliance of Brazil, Argentina, and Uruguay. Triggered by a regional crisis over Uruguay and rival claims along the Plata river system, it ended with Paraguay's occupation, the death of its president, and demographic and territorial losses that shaped the country for a century.
Events
Brazil Intervenes in Uruguay, and Paraguay Declares War
In 1864, Brazil intervened in a Uruguayan civil war on behalf of the Colorados against the Blanco government, which was allied with Paraguay's president, Francisco Solano López. López warned Brazil that an attack on Uruguay would be treated as an attack on Paraguay; when Brazilian forces invaded Uruguay in August and installed a pro-Brazilian government, Paraguay seized the Brazilian steamer Marquês de Olinda in the Paraguay River in November. On 13 November 1864, Paraguay declared war on Brazil, opening a conflict that would grow into South America's deadliest war.
Location: Asunción, Paraguay
Paraguay Invades Mato Grosso
In late December 1864, a Paraguayan column under Colonel Francisco Resquin struck into Brazil's remote province of Mato Grosso, capturing the fortress of Fort Coimbra on 27 December and the provincial capital of Corumbá in January 1865. The invasion, launched months before the Triple Alliance was formalized, was meant to punish Brazil and secure an alternative route to the sea via the Paraguay River system.
Location: Mato Grosso, Empire of Brazil
The Treaty of the Triple Alliance
On 1 May 1865, Argentina, Brazil, and Uruguay signed a treaty in Asunción creating the Triple Alliance against Paraguay, weeks after Paraguayan forces had occupied the Argentine province of Corrientes. The treaty committed the allies to continuing the war until Paraguay's government was overthrown and required Paraguay to bear the cost of the war, while leaving territorial compensation to be settled after victory.
Location: Asunción, Paraguay
The Battle of Riachuelo
On 11 June 1865, a Paraguayan squadron under Commodore Pedro Ignacio Meza attempted to slip past the Brazilian fleet under Admiral Barroso at Riachuelo on the Paraná River. The Paraguayans rammed and boarded a Brazilian vessel in the early exchange, but Brazilian gunfire disabled most of the Paraguayan ships, and the battle ended with the squadron destroyed or beached and roughly 250 Paraguayan sailors dead against about 30 Brazilian casualties.
Location: Riachuelo River, Corrientes Province, Argentina
The Siege of Humaitá Begins
Humaitá, a fortress town on a bend of the Paraguay River protected by chain booms and shore batteries, was the anchor of Paraguay's defensive strategy: no allied fleet could reach the capital at Asunción without passing its guns. An allied army landed at Paso de Patria in April 1866 and began the campaign against the position, while the Brazilian navy tried and failed to force the batteries in a bombardment that May.
Location: Humaitá, Paraguay
The Battle of Tuyutí
On 24 May 1866, López attacked the allied camp at Tuyutí with about 24,000 men against roughly 32,000 allied troops under Mitre. The Paraguayans briefly overran part of the camp and captured allied supply trains, but the assault was repulsed at terrible cost; Paraguayan losses ran into the thousands, including most of the officers of several veteran regiments.
Location: Tuyutí, Paraguay
The Battle of Curupayty
On 26 September 1866, an allied force of about 20,000 men attacked the Paraguayan position at Curupayty, defended by perhaps 5,000 soldiers behind earthworks. Paraguayan artillery and musketry cut down the attacking columns in the open ground; the allies lost around 8,000 men while Paraguay reported only a few hundred casualties, making it the most lopsided allied defeat of the war.
Location: Curupayty, Paraguay
The Fall of Humaitá
In February 1868, a Brazilian naval squadron slipped past the Humaitá batteries on a dark night, outflanking the fortress from downstream and cutting its supply line. Cut off and under bombardment, the garrison began evacuating by canoe in July, and by 5 August about 1,300 Paraguayan prisoners had been taken as the campaign ended after nearly three years.
Location: Humaitá, Paraguay
The Fall of Asunción
Brazilian forces under the Count of Eu entered Asunción on 5 January 1869, occupying a capital whose population had fled into the countryside. The city was sacked, and the Palace of the López family became the allied headquarters; the occupation installed a pro-Brazilian government that would dominate Paraguayan politics for decades.
Location: Asunción, Paraguay
The Death of López at Cerro Corá
On 1 March 1870, Brazilian cavalry caught up with Francisco Solano López and about 400 followers at Cerro Corá, about 454 km (280 miles) northeast of Asunción. López was killed in the final skirmish, reportedly refusing offers to surrender, and his death ended the war after five years and four months.
Location: Cerro Corá, Paraguay