quality:corruption
Treaty of Madrid

On January 13, 1750, King John V of Portugal and Ferdinand VI of Spain signed the Treaty of Madrid, in which both parties sought to establish the borders between Brazil and Spanish America, admitting that the Treaty of Tordesillas, as it had been envisioned in 1494, had been superseded, and was considered void. Spanish sovereignty was acknowledged over the Philippines, while Portugal would get the territory of the Amazon River basin. Portugal would relinquish the colony of Sacramento, on the left bank of the River Plata in modern-day Uruguay, while getting the territory of the Seven Missions.

Following the Guarani War, the treaty was annulled by Spain and Portugal in the Treaty of El Pardo (1761). The border was eventually settled in the First Treaty of San Ildefonso in 1777, with Spain acquiring territories east of the Uruguay River and Portugal acquiring territories in the Amazon Basin.