Treaty of Madrid
Spain and Portugal redrew the line dividing South America in 1750, abandoning the meridian they had agreed in 1494. The Treaty of Tordesillas had drawn a north-south line 370 leagues west of the Cape Verde islands, which nobody could locate accurately and which in any case bore no relation to where anyone actually lived. Portuguese bandeirantes had pushed hundreds of miles west of it hunting for gold and for Indigenous captives, and Portuguese settlement in the Amazon basin and Mato Grosso was an accomplished fact. The Treaty of Madrid replaced the meridian with the principle of uti possidetis — that each crown kept what it effectively occupied — and drew a border along rivers and watersheds that is roughly the border of Brazil today. Portugal gave up the colony of Sacramento on the Río de la Plata in exchange. The unresolved part was the Guaraní missions east of the Uruguay river. Seven Jesuit reductions with some 30,000 inhabitants, self-governing communities with their own militia, printing presses and orchestras, were transferred to Portuguese territory with instructions to move west and leave everything behind. They refused, and the combined Spanish and Portuguese armies fought the Guaraní War from 1754 to 1756 to enforce it, killing thousands. The episode contributed directly to the expulsion of the Jesuits from Portugal in 1759, from France in 1764, from Spain in 1767, and to the suppression of the order in 1773. The treaty was annulled in 1761 and its principle survived anyway. The principle it introduced outlived every border it drew. Uti possidetis became the rule by which the Spanish American republics fixed their frontiers on independence, and it was adopted again by the Organisation of African Unity in 1964 to freeze colonial boundaries across a continent.
- Year: 1750 CE
- Category: Political
