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Events on Wednesday 1 October 1777 1
1777Treaty of San IldefonsoSpain and Portugal settle South American bordersSpain and Portugal signed a treaty resolving longstanding border disputes in South America, with Portugal ceding Colonia del Sacramento to Spain in exchange for territory further north. The agreement redrew colonial boundaries along the Rio de la Plata region. It followed a brief war between the two crowns over the disputed territory.