evidence: Annexation and independence [edit]In 1811, José Gervasio Artigas, who became Uruguay's national hero, launched a successful revolt against Spain, defeating Spanish forces on May 18 in the Battle of Las Piedras. He then liberated Montevideo from the centralizing control of Buenos Aires, and in 1815 declared the Liga Federal. In August 1816, forces from Brazil invaded the Banda Oriental (present-day Uruguay) with the intention of destroying the Liga Federal. The Brazilian forces, thanks to their numerical and material superiority, occupied Montevideo on January 20, 1817, and after struggling for three years in the countryside, defeated Artigas in the Battle of Tacuarembó. [...] Border disputes [edit]A longstanding border dispute involving territory in the vicinity of Masoller exists between Uruguay and Brazil, although this has not harmed close diplomatic and economic relations between the two countries. The disputed area is called Rincón de Artigas/Rincão de Artigas Location -31.00, -55.95), and the dispute arises from the fact that the treaty that delimited the Brazil-Uruguay border in 1861 determined that the border in that area would be a creek called Arroio da Invernada, but the two countries disagree on which actual stream is the so-named one.[11]