This treaty ended the Cisplatine War and formally established Uruguay as an independent state, recognized by both Brazil and Argentina.
Key Facts
- Date signed
- 27 August 1828
- Signing parties
- Empire of Brazil and United Provinces of the Río de la Plata
- Mediating power
- United Kingdom of Great Britain
- Treaty ratified
- 4 October 1828, in Montevideo
- Conflict ended
- Cisplatine War
Location
Cause → Event → Consequence
The Cisplatine War erupted between the Empire of Brazil and the United Provinces of the Río de la Plata over the disputed Banda Oriental region. Neither side achieved a decisive military victory, and prolonged conflict threatened regional stability, prompting British diplomatic intervention to broker a negotiated settlement.
Between 11 and 27 August 1828, representatives of Brazil and the United Provinces met in Rio de Janeiro under British mediation. On 27 August they signed the Preliminary Peace Convention, a bilateral treaty that terminated hostilities and recognized Uruguay as an independent state, separate from both Brazil and Argentina.
Uruguay's independence, established by the convention, was formally ratified by both signatories in Montevideo on 4 October 1828, definitively sealing the new nation's sovereign status. The treaty reshaped the political boundaries of the Southern Cone and ended Brazilian territorial claims over the Banda Oriental.
Political Outcome
Uruguay recognized as an independent state by both Brazil and Argentina; Cisplatine War ended.
Banda Oriental contested between Brazil and the United Provinces of the Río de la Plata
Uruguay established as an independent sovereign state