The First Treaty of San Ildefonso was signed on October 1, 1777 between the Spanish Empire and the Portuguese Empire. The agreement mainly settled territorial disputes in the Río de la Plata region. Based on the terms of the agreement, Spain ceded territories in Brazil to Portugal (i.e. Amazon Basin) in return for maintaining control over the Banda Oriental (i.e. Uruguay). Also, Portugal ceded to Spain the island of Fernando Poo and territories on the African coast between the Niger and Ogoue estuaries. The treaty dismissed the territory of Pombal and reaffirmed the Treaty of Madrid (1750). October 1 is the 274th day of the year (275th in leap years) in the Gregorian calendar. ... Year 1777 (MDCCLXXVII) was a common year starting on Wednesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 11-day slower Julian calendar). ... Military flag of the Spanish Empire from the 16th century up to 1843. ... Maximum extent of Portuguese colonial possessions in the 16th century. ... RÃo de la Plata in relation to Uruguay and Argentina A satellite view of the estuary The RÃo de la Plata (Spanish: Silver River) â which is often referred to in English-speaking countries as the River Plate (as in the Battle of the River Plate), or sometimes as... Amazon River basin The Amazon Basin is the part of South America drained by the Amazon River and its tributaries. ... Bioko is an island off the west coast of Africa in the Gulf of Guinea, formerly called Fernando Po or Fernando Poo. ... Coat of Arms Pombal (pron. ... There is more than one Treaty of Madrid: Treaty of Madrid (1526), in which France renounced claims in Italy, surrendered Burgundy to Spain, and abandoned suzerainty over Flanders and Artois Treaty of Madrid (1670), in which Spain recognized British possessions in the Caribbean Sea, such as Jamaica and the Cayman... Events March 2 - Small earthquake in London, England April 4 - Small earthquake in Warrington, England August 23 - Small earthquake in Spalding, England September 30 - Small earthquake in Northampton, England November 16 â Westminster Bridge officially opened Jonas Hanway is the first Englishman to use an umbrella James Gray reveals her sex...