The Paraguayan War, also known as the War of the Triple Alliance, was a South American war that lasted from 1864 to 1870. It was fought between Paraguay and the Triple Alliance of Argentina, the Empire of Brazil, and Uruguay. It was the deadliest and bloodiest inter-state war in Latin American history. Paraguay sustained large casualties, but even the approximate numbers are disputed. Paraguay was forced to cede disputed territory to Argentina and Brazil. The war began in late 1864, as a result of a conflict between Paraguay and Brazil caused by the Uruguayan War. Argentina and Uruguay entered the war against Paraguay in 1865, and it then became known as the "War of the Triple Alliance."
The Battle of Riachuelo was a large and decisive naval battle of the Paraguayan War between Paraguay and the Empire of Brazil. By late 1864, Paraguay had scored a series of victories in the war, but on 11 June 1865, its naval defeat by the Brazilians on the Paraná River began to turn the tide in favor of the allies.
The Battle of Tuyutí was a Paraguayan offensive in the Paraguayan War targeting the Triple Alliance encampment of Tuyutí. It is considered to be the bloodiest battle ever in South America. The result of the battle was an Allied victory, which added to the Paraguayan troubles after the loss of its fleet in the Battle of Riachuelo.
Francisco Manuel Barroso, Baron of Amazonas was a Brazilian admiral of the Imperial Brazilian Navy.
The Battle of Acosta Ñu, also known as the Children's Battle in Paraguay and the Battle of Campo Grande in Brazil, took place on 16 August 1869. It was the last major engagement of the Paraguayan War between the Triple Alliance and Paraguay. The 3,500 poorly armed Paraguayans, mostly boys between nine and fifteen years old, old men and wounded combatants, confronted 20,000 Brazilian and Argentine veteran soldiers.
The military history of Brazil comprises centuries of armed actions in the territory encompassing modern Brazil, and the role of the Brazilian Armed Forces in conflicts and peacekeeping worldwide. For several hundreds of years, the area was the site of intertribal wars of indigenous peoples. Beginning in the 16th century, the arrival of Portuguese explorers led to conflicts with the indigenous peoples; a notable example being the revolt of the Tamoio Confederation. Sporadic revolts of African slaves also marked the colonial period, with a notable rebellion led by Zumbi dos Palmares. Conflicts were fought with other European nations as well – two notable examples being the France Antarctique affair, and a conflict with the Netherlands in the early 17th century over control of much of Northeastern Brazil. Although Portugal retained its possessions during conflicts with other nations, it lost control of the colony after the Brazilian war of Independence, which led to the establishment of the Empire of Brazil.
The Platine War was fought between the Argentine Confederation and an alliance consisting of the Empire of Brazil, Uruguay, and the Argentine provinces of Entre Ríos and Corrientes, with the participation of the Republic of Paraguay as Brazil's co-belligerent and ally. The war was part of a decades-long dispute between Argentina and Brazil for influence over Uruguay and Paraguay, and hegemony over the Platine region. The conflict took place in Uruguay and northeastern Argentina, and on the Río de la Plata. Uruguay's internal troubles, including the longrunning Uruguayan Civil War, were heavily influential factors leading to the Platine War.
The siege of Humaitá was a military operation in which the Triple Alliance flanked, besieged and captured the Fortress of Humaitá, a Paraguayan stronghold that was referred to as the Gibraltar of South America. It fell on 26 July 1868. It can be considered the key event of the Paraguayan War since the fortress had frustrated the allied advance into Paraguay for more than two years. However it did not surrender as the defenders escaped, most of them to fight another day.
José Luís Mena Barreto was an army officer, politician and monarchist of the Empire of Brazil. He came from a wealthy family with a tradition of military service. José Luís entered the army in 1836, during the Ragamuffin War, a secessionist rebellion. The conflict lasted for almost ten years, and he fought in several military engagements at that time.
Events in the year 1866 in Brazil.
The Battle of Boquerón was fought on 16 July 1866 and the Battle of Sauce on 18 July 1866, between an allied force of Uruguayans, Brazilians, and Argentines on one side and Paraguay on the other in the Paraguayan War. The Spanish-born Uruguayan officer León de Pallejas (1816–1866) and the Paraguayan officer Elizardo Aquino were killed in the battle.
The Battle of Tatayibá was a cavalry engagement between a Paraguayan force led by future president Bernardino Caballero and a Brazilian force led by Luís Alves de Lima e Silva, then Marquis of Caxias. The Brazilians, outnumbering the Paraguayans nearly 3 to 2, were victorious.
Events in the year 1867 in Paraguay.
The Angostura Fortress was a Paraguayan Army fortification, located by the Pikysyry stream, in Paraguayan territory. The Paraguayan War,[A], was a South American war fought from 1864 to 1870 between Paraguay and the Triple Alliance nations. Angostura Fortress was a battery of Paraguayan defense line fortifications strategically located along Lomas Valentinas. The Paraguayan units surrendered the fortification on 27 December 1868, which were then occupied by Imperial Brazilian Army forces on 30 December 1868. This led to a series of victorious battles won by Triple Alliance armies.
The capture of the steamer Marquês de Olinda was a Paraguayan naval action carried out on 12 November 1864, in Potrero-Poña, on the Paraguay River, which consisted of the capture of the Brazilian merchant ship and all on board. Paraguayan president Solano López ordered the imprisonment in response to the Brazilian invasion of Uruguay, before any formal declaration of war between Paraguay and the Empire of Brazil.
The Battle of Jaguarí was a naval confrontation in the Paraguayan War between Brazilian and Paraguayan flotillas, which took place on March 23, 1866 at the mouth of the Jaguari River, Paraná River. At the time, aboard the steamer Cisnei, were admiral Joaquim Marques Lisboa and generals Osório, Mitre and Flores. The ship was escorted by the ironclad Tamandaré and the gunboats Beberibe and Henrique Martins, and was on a reconnaissance mission on the Paraná River to the mouth of Jaguari. However, at eleven o'clock in the morning, the Paraguayan steamer Gualeguai and a towed boat found the Brazilian flotilla in Jaguari and immediately started bombing them, without causing damage. Only Tamandaré ran aground on the island of Itapiru. Despite the confrontation, the region's recognition proved to be useful to the allies, as the future location for the landing of the Triple Alliance troops that would initiate the invasion of Paraguayan territory was defined.
The Battle of Itapirú took place during the Paraguayan War on April 17, 1866, after Brazil's capture of Purutué Bank a week earlier. The battle marked the beginning of the Triple Alliance's invasion of Paraguay.
The Battle of Arroio Hondo, also known as Combat of Penimbu or Puru-Hué (Peru-Huê), took place on 3 August 1867, during the Paraguayan War.
The Battle of Estero Rojas took place on 24 September 1867, when a Brazilian convoy, coming from Tuyutí to Tuju-Cuê, was attacked by Paraguayan troops under the command of Vallois Rivarola.
The Humaitá campaign or the Cuadrilátero campaign was the third, longest and deadliest campaign of the Paraguayan War. The campaign lasted from 16 April 1866 to 5 August 1868. After the initial Paraguayan success in the Mato Grosso campaign and its failure in the Corrientes campaign, the armed forces of the Triple Alliance, Argentina, the Empire of Brazil and Uruguay, invaded the south of Paraguay. At a very short distance, they found the Paraguayan defensive device made up of four fortifications, the so-called "Cuadrilátero", which obstructed the passage to Asunción both by land and by the Paraguay River. A long series of battles cost huge numbers of casualties on both sides, with operations coming to a complete halt after the allied defeat at the Battle of Curupayty. Casualties on both sides were even higher from disease than from battle due to a cholera epidemic which was added to the appalling food and sanitary conditions.
Paraguay 
Empire of Brazil 
