As far back as 1680, Uruguay had been a bone of contention between Portugal and Spain, but at the outbreak of the Revolution in 1810, the country was Spanish and was an integral part of the Viceroyalty of the Plata. Montevideo became, as we have seen, the center of Spanish resistance to the movement of independence, and following Artigas' victory at Las Piedras, was besieged by his troops and the Argentine forces under Rondeau. The city would have fallen, but news of the defeat at Huaquí reached Buenos Aires, and the besiegers were recalled to protect the Argentine soil. Civil strife between Buenos Aires and Artigas ensued because the latter stood for a federal republic, while Buenos Aires, of course, was unitarian, and wished to retain her supremacy over the provinces. In 1817, Artigas became embroiled with the Portuguese, who routed him and captured Montevideo. Rivera, Oribe, and Lavalleja, lieutenants of Artigas, and later famous in the history of Uruguay, had to take refuge in the interior. Artigas himself retired to Paraguay and died there of old age in 1850. By 1821 all resistance to Brazil was at an end. Rivera and many of the other _caudillos_ had accepted commissions in the Brazilian army of occupation. Uruguay itself had become the cisplatine province of Brazil, and so matters stood until the 19th of April, 1825, when Lavalleja gathered the famous "Treinta y Tres", a band of thirty-three Uruguayan patriots, and landed in Uruguay from the Argentine province of Entre Ríos. So great was their success that by May of that year, the whole country was in revolt against the Brazilians, and the forces of the Empire were confined within Montevideo and La Colonia. The patriot victory at Sarandí under Lavalleja and Rivera caused Argentina to declare formally that Uruguay was again a part of the Argentine Confederation. War between Argentina and Brazil was declared and at Ituzaingó, far within the Brazilian territory, the Brazilians suffered a terrible defeat in 1827. This, as we saw above, happened during Rivadavia's presidency, and led to his resignation because of the peace signed by his envoy. The upshot of the whole matter was that both Brazil and Argentina gave up all claims to Uruguay and guaranteed its independence as a separate republic for five years. Argentina was being torn by federalist and unitarian dissensions, and could not press her claim. In Uruguay itself there were rival factions led by Rivera and Lavalleja, who held the presidency in turn, Rivera becoming the first official head of the nation in 1830.