In 1814, the famous Admiral Brown blockaded Montevideo by sea and Alvear attacked by land with 4000 troops which had crossed to Colonia. The Spaniards sailed out on May 16th. to meet the Argentines, but by strategy Brown got between them and land and completely destroyed their fleet. Alvear laid siege to Montevideo and took it by assault on June 22nd. This was an important victory, for it gave control of the sea and rivers to the Argentine, and lessened the danger of attacks on Buenos Aires by expeditions from Spain. San Martín became convinced that the conquest of Lower Perú through Upper Perú was impossible--that only a defensive warfare could be successfully waged in the north, and that the real road to Lima was via Chile. He kept his opinion secret, but pleading ill-health asked for the post of Governor of the Province of Cuyo with headquarters in Mendoza. He was given this appointment in August, 1814, and upon arrival began to organize from the limited means at his command what he subsequently called the "Army of the Andes". He worked on this for two years, hiding his plan from everybody as far as he could. At the end of that period, when the Tucumán Congress inaugurated its labors, San Martín was one of the dominant figures in the Argentine. It is hard to understand how he acquired this prestige, for his only military exploit in the Argentine was the battle of San Lorenzo, and we have seen how small were the proportions of that event. His command of the Army of Upper Perú had not been marked by anything of importance, and he had voluntarily sought out a distant and little visited point, away from the main lines of travel and segregated from what were considered the seats of war. Yet in 1816, he was one of the greatest moral influences in the country. He did not attend the Tucumán Congress, although the Presidency of it would have been his for the asking. His mouthpiece was Godoy Cruz, and his written advice and instruction to that faithful representative afford much of the existing illuminating information covering the period.