At this stage the conflict between Unitarians and federals around Montevideo acquired a transcendental significance. Brazil intervened once more in the affairs of La Plata. Impregnable as Paraguay under Lopez, the Eastern Province continued the war against Oribe, its ex-president, and against the legions of the Argentine tyrant. A noble crusader in the cause of liberty, Garibaldi, at the head of the Uruguayan squadron which defended Montevideo, gave the struggle a romantic character. Oribe, a genius of destruction, ravaged the country, and besieged Montevideo by land in 1843. Foreigners: French, Italians, Turks, and natives, defended the threatened city. England, France, and Brazil at first offered their mediation, which was refused by Oribe; they then sent squadrons to defend the autonomy of Uruguay and to insure the free navigation of the River Parana in the interests of European commerce. After a long war of heroic conflicts Urquiza, the leader of the armies in alliance against the autocracy of Rosas, put Oribe to flight (1861) and saved Montevideo from the Argentine peril. Lavalleja and Rivera, the great _caudillos_ in the struggle for liberty, were rival claimants for power and moral influence. Rivera, like Artigas, represented an aggressive patriotism, hostile to all outside influence; his ideal was national integrity. Generous, anarchical, of the native type, he was more liberal and more of a democrat than Lavalleja; he defended all liberties--liberty of conscience, of industry, of the press. A nomadic _gaucho_, he organised and led guerilla forces through a campaign of incessant skirmishes. Lavalleja, imperfectly educated, rude, authoritative, half a Spaniard in his pride and his colonial methods, was the leader of the aristocratic and cultivated classes. More conservative and more politic than Rivera, he opposed the rural democracy, {131} and desired an orderly independence, a disciplined liberty; in government he was a tyrant. He alienated the supporters of Rivera, dissolved the Chamber of Representatives, reformed the administration of justice, and estranged the authorities of the departments. Rivera, President from 1830 to 1834 and from 1838 to 1843, was--like the majority of the American _caudillos_--a zealous protector of commerce and industry. The national revenues mounted by 27 per cent.; imports and exports increased; the population was doubled, and schools and libraries were founded. Rivera exterminated the Charrua Indians, who pillaged in town and country, fostered the stock-raising industry, and, in his democratic enthusiasm, prohibited the slave trade in 1839 and freed the slaves in 1842.