The 1851 Boundary Treaty established between Brazil and Uruguay as a result of the Uruguayan Civil War and conflicts with Brazil and Argentina; the result of the treaty was a step towards the acceptance of Uruguay's independence from neighboring territories.
[1] Uruguay rewarded Brazil's financial and military support by signing five treaties in 1851 that provided for perpetual alliance between the two countries.
The treaties also allowed joint navigation on the Uruguay River and its tributaries, and tax exempted cattle and salted meat exports.
However, a dispute still exists in the vicinity of Masoller over which creek was meant to mark the border in that area.
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