South America 1869: Fall of Asunción
In late 1867 Brazilian and Argentine forces converged on the Paraguayan Fortress of Humaitá, capturing it in July the following year after a lengthy siege. The loss of Humaitá was a critical blow to Paraguay and in January 1869 advancing Brazilian troops occupied Asunción.
Patagonia was regarded as terra nullius by Britain and France until 1881 (and thus shown as a separate state in most maps of the period). Their main concern, shared with the United States, was to prevent any nation restricting navigation through the Straits of Magellan.
27 Mar 1867 Treaty of Ayacucho▲
Dr. Felippe Lopes Netto, on behalf of the Empire of Brazil, signed the Treaty of Friendship and Limits with Dr. Don Mariano Donato Muñoz, of the Republic of Bolivia, at Ayacucho. The treaty established the boundary between the two countries, most importantly assigning what would become the Brazilian state of Acre - at the time the Acre River itself was undiscovered - to Bolivia.
12 Apr–21 Jun 1867 Siege of Mexico City▲
Republican forces under Porfirio Díaz - supported by the 3,000-strong American Legion of Honor - arrived on the outskirts of Mexico City, occupying the outlying towns of Chapultepec, Tacubaya, and Guadalupe. On 18 June 1867, following news of the capture of Emperor Maximilian, the French and Austrian troops defending the capital declared their neutrality and entered into negotiations with the Republicans. With the loss of their European allies and facing starvation, the Imperial defenders surrendered the capital on 20 June; Díaz entered the city the following day.
2 Nov 1867–24 Jul 1868 Siege of Humaitá▲
In November 1867, Brazilian and Argentine forces began their land and riverine offensive around the heavily fortified Paraguayan complex at Humaitá. The Brazilian navy broke through on 19 February 1868, repelling fire from the fortress to send a river squadron under Delfim de Carvalho up the Paraguay River. With the Allies in control of the river, the Paraguayans began to withdraw; Humaitá itself was completely abandoned by the time it fell to assault in late July.
19 Aug 1868–5 Jan 1869 Pikysyry Campaign▲
After the fall of Humaitá, Paraguay established a new defensive line from Angostura up Pikysyry Creek. While assigning 6,500 Argentine, 2,200 Brazilian, and 800 Uruguayan troops to guard this line, General Caxias secretly crossed the Paraguay River in October 1868 with 18,500 Brazilians to advance up the sparsely inhabited western bank. Recrossing the river at San Antonio in early December, the Brazilian force fell upon the Paraguayan rear, defeating them at Itororó, Avay, and Itá-Ibaté and clearing the way to Asunción.
5 Jan 1869 Fall of Asunción▲
After roundly defeating the Paraguayans in December 1868, Caxias's mostly Brazilian Allied army marched into Asunción on 5 January. Largely deserted, the Paraguayan capital was subjected to extended looting. Paraguayan President Solano López withdrew into the interior, setting up new capitals first at Luque, then at Piribebuy.