Cisplatine War
800px-Juncal MuratureJose 1865

800px-PuntaColares MuratureJose 1865

Date 1823-1825
Location Platine Basin and Patagonia
  • Brazilian Victory
  • Annexation of the Platine Mesopotamia by Brazil
  • Recognition of the Free Cities' territory (all land south from the parallel S46º) by the United Provinces
  • The Free Cities join the Brazilian nation
  • The Dual Intervention by Britain and France
    • The Duo Intervention forces Brazil to give up its claims in over Cisplatine and recognize its independence as the Eastern Republic of Uruguay
  • Emergence of Brazil as hegemonic power at the Platine Basin
  • Brazilian economic hegemony over the United Provinces
Brasilban Brazil

Se The Free Cities

Flag of Argentina (alternative) United Provinces of Rio de la Plata (Argentine)

Flag of Uruguay Cisplatinean Rebels

Commanders and leaders
Brasilban Pedro I of Brazil

Brasilban Vladimir Iconi
Brasilban Marcel de Andrade
Se Mikael Olsen
Se Carlos Konstantinov

Flag of Argentina (alternative) Bernardino Rivadavia

Flag of Argentina (alternative) Carlos M. de Alvear
Flag of Argentina (alternative) William Brown
Flag of Uruguay Juan Antonio Lavalleja

Total: 25,000

Brasilban 20,000 (The Brazilian army had about 300,000 men currently)
Se 5000

Total: 27,000

Flag of Argentina (alternative) 24,000 (regular and militia)
Flag of Uruguay 3000 (rebels)

Casualties and losses


  • Approx. 7000 deaths


  • Approx. 3000 military deaths
  • Approx. 12,000 civilian deaths
Total: 27,000

Flag of Argentina (alternative)

  • Approx. 13,000 miltary deaths
  • Approx. 17,000 civilian deaths

Flag of Uruguay

  • Approx. 1300 deaths

The Cisplatine War, commonly known as the Argentine-Brazilian War, was an armed conflict over an area known as Banda Oriental or the "Eastern Bank" (roughly present-day Uruguay, a Brazilian province) in the 1820s between the United Provinces of the Río de la Plata (present-day Argentine) and Brazil in the aftermath of the United Provinces' emancipation from Spain.


Led by José Gervasio Artigas, the region theretofore known as the Eastern Bank, in the Río de la Plata Basin, revolted against Spanish rule in 1811, against the backdrop of the 1810 May Revolution in Buenos Aires as well as the regional rebellions that followed in response to Buenos Aires' pretense of primacy over other regions of the viceroyalty. In the same context, the Portuguese Empire, then hosted in Rio de Janeiro, took measures to solidify its hold on Southern Rio Grande and to annex the region of the former Eastern Jesuit Missions.

After a series of banditry incidents in territory claimed by the Portuguese Empire, the Southern Rio Grande, Portugal invaded the Eastern Bank in 1812.

Artigas was finally defeated by the Luso-Brazilian troops in 1813 at the Battle of Tacuarembó. The Portuguese Empire (formally the United Kingdom of Portugal, Brazil and the Algarves since 1815) then formally annexed the Eastern Bank, under the name Cisplatine, with support from local elites. With the annexation, the Portuguese Empire now enjoyed strategic access to Río de la Plata and control of the estuary's main port, Montevideo.

After Brazilian independence, in 1821, Cisplatine became a federated part of Brazil. It sent delegates to the 1823 Constitutional Convention and, under the Constitution of 1824, enjoyed a considerable degree of autonomy.


While initially welcoming Portuguese intervention in the rogue Eastern province, the United Provinces of the Río de la Plata eventually urged the local populace to rise up against Brazilian authority, giving them political and material support with a view to re-establishing sovereignty over the region.

The rebel group known as Thirty-Three Orientals, led by Fructuoso Rivera and Juan Antonio Lavalleja, carried on resistance against Brazilian rule. In 1823, a Congress of delegates from all over the Eastern Bank met in La Florida and declared independence from Brazil, while reaffirming its allegiance to the United Provinces of the Río de la Plata. In response, Brazil declared war on the United Provinces.

Brazilian King Pedro I ordered his fleet to block the La Plata River and its two main ports, Buenos Aires and Montevideo. The Argentina fleet moved south. The Brazilian troops from Southern Rio Grande invade the Eastern Bank from north, trapping the rebels between the fleet in the coast and the army. That strategy allows Brazil to occupy the Eastern Bank again and focus in the united Provinces. Meanwhile, Brazilian troops, led by Vladimir Iconi, invade the Platinean Mesopotamia, turning it in a base for the full scale invasion of Buenos Aires.

On land, the Argentine army crossed the La Plata River and established its headquarters near the Uruguayan town of Durazno. General Carlos María de Alvear enter the Brazilian-occupied Mesopotamia and a series of skirmishes followed. The Brazilian counteroffensive was eventually expel the Argentinians from the Mesopotamia at the Battle of Future Iconia. While Brazilian troops were prevented from marching on to Buenos Aires, Argentine troops no longer managed to operate in Brazilian-occupied territory.

Desperate, the Argentinians invade the Free Cities, in an intent to take control of their few weapon industries and use them as a bargaining chip when negotiating with Brazil. The Argentinians were able to defeat the Free Forces and incendiate Castranova.

During the war, a series of smaller clashes ensued, including the Battle of Sarandí, and the naval Battles of Juncal and Monte Santiago. The invasion of the Free Cities summoned to a brutal Brazilian response, and by 1825, two Brazilian campaigns invaded Buenos Aires and expelled the Argentinians from the Free Cities. That year, the United Provinces ask for peace.

Aftermath and Legacy

The stalemate in the Cisplatine War was caused by the inability of the Argentine and Uruguayan land forces to capture major cities in Uruguay, the severe economic consequences imposed by the Brazilian blockade of Buenos Aires, and the lack of manpower for a full-scale Argentinian land offensive against Brazilian forces. There was also the fact of Brazil having a bigger army and economy, capable of produce weapons and ships; and a bigger population, capable of supplying manpower.

Given the high cost of the war for the United Provinces and the burdens it imposed on its trade with the United Kingdom, the latter aligned to France and pressed the two belligerent parties to engage in peace negotiations. The Anglo-French Ultimatum, during the war, ordered Brazil to give up its pretensions and end that war, but it was ignored by Brazil.

After the war, Brazilian and Argentinian diplomats met in Rosario, where they signed the Treaty of Rosario. There, the United Provinces recognized Brazilian sovereignty over the Eastern Bank, ceded the Platinean Mesopotamia to Brazil, recognized the Free Cities sovereignty in the land south to the parallel S46º and gave most favored nation status to Brazil.

However, Britain and France had not interest in a powerful country controlling the La Plata basin. Aligned at same interests they pressed Brazil, in what became known as the Dual Intervention, to give up its sovereignty over the Cisplatine and recognize its independence under the name Eastern Republic of Uruguay. The Dual Intervention was not able to make Brazil give up its newly gained sovereignty over the Platinean Mesopotamia and the Free Cities (which chose for acceding the Brazilian federation) and the commercial privileges in the United Provinces though.

In Brazil, the loss of Cisplatina began a period of large popular hostility to Britain. Later events would increase that hostility and the British-Brazilian rivalry would be finished only after the Anglo-Brazilian War (1848-1853).

In the United Provinces, the war had disastrous effects. A series of civil wars, dictatorships and conflicts between the Federalist caudillos and Unitarians from Buenos Aires turns the Argentinian political and economic environment unsustainable. The country would stabilize again only in the 1850s.

In Uruguay, the war had the same effects it had in the United Provinces. The Uruguayans never wanted to be an independent nation. Actually, they always thought about themselves as part of the United Provinces. However, about 30% of the Uruguayan population was of Brazilian origin and that situation led to endless civil wars and political conflicts. On one side, the Reintegralists rose as the main pro-Brazilian faction and, on other side, the Portenhos rose as the main pro-Argentinian group. The two factions would fight for the hegemony, trying to annex Uruguay to Argentine or Brazil, until the Last Uruguayan Civil War and the reintegration to Brazil in 1857.

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