The Treaty of El Pardo was signed on March 11, 1778 between Queen Maria I of Portugal and King Charles III of Spain. Based on the terms of the treaty, Queen Maria ceded the islands of Annobón and Bioko (Formosa) to King Charles, as well as the Guinea coast between the Niger River and the Ogoue River. In exchange for these territories, the Portuguese acquired new possessions in South America. The island of Formosa (named Fernão do Pó during Portuguese rule) was officially renamed and recognized as Fernando Poo.
