territory, in mid-1826, President Rivadavia appointed Alvear as commander in chief of the Argentine army, which was in mutiny. Alvear quickly restored discipline and put the troops in fighting condition. By the end of the year, after only three months on the job, he took the initiative and launched an invasion of the Brazilian province of Rio Grande do Sul. Among Alvear's objectives was to promote a slave rebellion which would force the Emperor to seek an armistice. During the first months of 1827 Cisplatine War, the Argentine Army entered Brazilian territory and defeated the Brazilians at Bagé, Ombú, Camacuá and the great Battle of Ituzaingó, probably the most important victory of his career. It was his brilliant and fearless conduct during this campaign, and the memorable victory which ended it, that made controversial Alvear a national hero among Argentine people ever since. However, internal dissensions in Argentina and the signing of what was perceived to be a humiliating peace treaty brought down Rivadavia's presidency. Without any political backing or support from Buenos Aires. Alvear tendered his resignation and returned to Buenos Aires. When he arrived in the capital, he realized he had been removed by the new government, which did everything possible to discredit him and Rivadavia. Alvear and Rosas In 1829 Juan Manuel de Rosas appeared in the Argentine political scene, inaugurating a controversial regime that on and off would last almost 23 years. Alvear was one of the leaders of the opposition and, in 1832, Rosas appointed him ambassador to the United States, as a way of neutralizing his political ambitions. A change in government the following year allowed Alvear to remain in Buenos Aires. However, when Rosas returned to power in 1835, he again tried to get rid of Alvear, who he suspected was conspiring against his government. Argentina's first ambassador to the United States In early 1837, after discovering evidence that linked Alvear to a new conspiracy, Rosas appointed him Argentina's first minister plenipotentiary to the United States. However, he was only able to depart the following year. Alvear spent the rest of his life as ambassador in the U.S. and died in his house in New York in November 1852. During his residence in the United States, Alvear had the opportunity to meet and interact with important political figures such as Joel Roberts Poinsett, Daniel Webster, John Calhoun and James Buchanan, among others. Alvear's