Uruguay has been united to Brazil, but in 1825 it revolted against the Emperor, and, as might have been expected, Argentina took the part of her neighbour, and Brazil declared war. Assisted by Admiral Brown, an Irishman, the Argentines inflicted great loss upon Brazilian shipping, and Alvear took command of a large army, which invaded Rio Grande do Sul and completely defeated the Brazilians at Ituzaingo on February 20, 1827. This blow was decisive, and a treaty was made by which Rivadavia, distracted by domestic troubles and anxious to secure peace at any price, agreed that Uruguay should still remain a part of Brazil. His enemies had already spared no efforts to rouse prejudice and inflame public resentment against him. Appeals had been made to provincial jealousies, the issue of paper-money was alleged to be draining the country of the precious metals, and even his statesmanlike efforts to encourage immigration and the hospitality he offered to foreigners were matters of accusation against him. The treaty raised a storm of indignation, and had to be annulled. Rivadavia was so completely discredited by this transaction that on July 7, 1827, he was forced to resign, and thus the country lost probably the best constructive statesman she has produced--a loss which she could ill afford. Dorrego succeeded him, but in reality the Republic was showing a strong tendency to split up, and Lopez in Santa Fé, Ibarra in Santiago, Bustos in Cordoba, and Quiroga in Cuyo, possessed almost as much power as Dorrego at Buenos Aires. However, with the help of several of these men, he succeeded in ending the war by a compromise which left Uruguay an independent state. Argentina was thus free to devote herself to domestic warfare. Lavalle was now the head of the Unitarians, and he succeeded in expelling Dorrego from Buenos Aires. The latter fled to his estates and raised a body of adherents, but was captured and shot by Lavalle. The death of Dorrego cleared the way for a man who was destined to have a much longer political life than is usual in South America, and also to fill a much larger space in the eyes of the world. That man was Juan Manuel Rosas.