No sooner had Rivadavia assumed the presidency under the new order of things than dissension at home and warfare abroad threatened to destroy all that he had accomplished. Ignoring the terms of the constitution, the provinces had already begun to reject the supremacy of Buenos Aires, when the outbreak of a struggle with Brazil forced the contending parties for a while to unite in the face of the common enemy. As before, the object of international dispute was the region of the Banda Oriental. The rule of Brazil had not been oppressive, but the people of its Cisplatine Province, attached by language and sympathy to their western neighbors, longed nevertheless to be free of foreign control. In April, 1825, a band of thirty-three refugees arrived from Buenos Aires and started a revolution which spread throughout the country. Organizing a provisional government, the insurgents proclaimed independence of Brazil and incorporation with the United Provinces of La Plata. As soon as the authorities at Buenos Aires had approved this action, war was inevitable. Though the Brazilians were decisively beaten at the Battle of Ituzaingo, on February 20, 1827, the struggle lasted until August 28, 1828, when mediation by Great Britain led to the conclusion of a treaty at Rio de Janeiro, by which both Brazil and the Argentine Confederation recognized the absolute independence of the disputed province as the republic of Uruguay. Instead of quieting the discord that prevailed among the Argentinos, these victories only fomented trouble. The federalists had ousted Rivadavia and discarded the constitution, but the federal idea for which they stood had several meanings. To an inhabitant of Buenos Aires federalism meant domination by the capital, not only over the province of the same name but over the other provinces; whereas, to the people of the provinces, and even to many of federalist faith in the province of Buenos Aires itself, the term stood for the idea of a loose confederation in which each provincial governor or chieftain should be practically supreme in his own district, so long as he could maintain himself. The Unitaries were opponents of both, except in so far as their insistence upon a centralized form of government for the nation would necessarily lead to the location of that government at Buenos Aires. This peculiar dual contest between the town and the province of Buenos Aires, and of the other provinces against either or both, persisted for the next sixty years. In 1829, however, a prolonged lull set in, when Rosas, the gaucho leader, having won in company with other caudillos a decisive triumph over the Unitaries, entered the capital and took supreme command.