In the meanwhile Benavidez had laid siege to Colonia, the garrison of which, after a month's resistance, escaped by river to Montevideo. It was upon this latter place that the fortune of the Spanish dominion now hung. The scale of warfare was increasing in proportion to the importance of the issue. Shortly after the arrival of the reinforcements supplied by the Royalist fugitives from Colonia, Rondeau, in command of the Argentine troops, arrived to take charge of the attacking force, that now amounted to four thousand men. Artigas, now one amongst many, dropped in rank from commander to leader of horse. Rondeau had contrived to drag two heavy guns to the spot, and with these he opened fire upon Montevideo. Galled by a continuous bombardment, Elio took a more desperate step than was justified even by his situation. Carlota, the Queen of Portugal and the sister of Ferdinand VII. of Spain, had been established in Rio de Janeiro since the invasion of the peninsula by the Napoleonic armies. To her the Viceroy, seeing the last foothold of power slipping from beneath him, sent an urgent message for assistance. Ere the response to this appeal became evident the condition of the beleagured town had changed. Discouraged by the serious defeat at Huaqui of the army of Peru, the revolutionary leaders of Buenos Aires were already contemplating a retirement from before Montevideo, when the blow engineered by Elio took effect. A swarm of Portuguese, under command of General Diego de Souza, entered the Banda Oriental from the north with the purpose of overrunning the country. The Buenos Aires Government, appalled by the new turn that affairs had taken, made the utmost haste to conclude an armistice with Elio. By the terms of the treaty the patriot forces were to retire from Montevideo, and Spanish authority was to be recognised throughout Uruguay in exchange for the return of Souza's forces to Brazil. Thus Elio's unscrupulous move had succeeded for the time being, and the first siege of Montevideo came to an end. A month after its conclusion Elio retired to Spain. The command he had left was now no longer worthy of the highest rank, and the departed Viceroy was succeeded by Vigodet in the minor capacity of Captain-General. Artigas had from the first bitterly opposed this treaty, by the terms of which the Orientales were to be left at the mercy of the Royalists. That he had right upon his side from his own point of view is undeniable, although it is difficult to see by what other means the Buenos Aires Government, caught between the Spaniards and the Brazilians, could have extricated themselves from their dilemma. The treaty once concluded, however, Artigas initiated a move that in itself proved the greatness of the man.