This transplantation had hardly been accomplished when the Spanish government took a step which revolutionised the administration of the southern half of the continent during the remainder of colonial times, and determined the future boundaries of the nations of South America. On the 1st of August, 1776, the Viceroyalty of Buenos Aires was created. All the territory south of Lake Titicaca was separated from the Viceroyalty of Peru, and the province of Cuyo was detached from the Captaincy-General of Chile. The new Viceroyalty covered the territory that has since become the four countries--Bolivia, Paraguay, Uruguay, and Argentina. In colonial times it was divided into eight "intendencias," of which the northern four covered the region that is now Bolivia and was then known as Upper Peru. The four southern intendencias were: Paraguay; Salta, covering the northwestern provinces; Cordoba, covering the central and western provinces; and, finally, Buenos Aires, which, besides the present province, included Santa Fe, the whole mesopotamian region, Uruguay, and the Jesuit country of the Upper Parana. The creation of the Viceroyalty was a reluctant and tardy reversal of the colonial policy which had steadfastly refused to recognise in Buenos Aires the inevitable outlet of the region. Although the four northern intendencias contained more than half the population, and Paraguay probably half the remainder, Buenos Aires was made the capital. Situated at the mouth of the great system of waterways, it was the natural commercial centre of the whole Viceroyalty. In fifty years it had doubled in population, while the old cities on the Bolivian plateau had remained stationary. In 1776 its population did not much exceed twenty thousand souls, but was rapidly increasing. Heretofore, it had been rather a resort of smuggling merchants than a centre of political and social influence. Nevertheless, from this unpromising root was to spring the spreading tree of South American independence. Buenos Aires is the only capital that never readmitted the Spanish authorities, once they had been expelled, and within her walls San Martin drilled the nucleus of the armies that drove the Spaniards out of Chile and Peru. [Illustration: AN OLD SPANISH CORNER IN BUENOS AIRES.] The alarming growth of the Portuguese power southward was another potent reason for the establishment of a strong and independent military jurisdiction at the mouth of the Plate. The Spanish government had at last determined on vigorous measures to take Colonia, drive the Portuguese from Rio Grande, and push the Spanish boundaries east to the original Tordesillas line. Pedro de Zeballos, the first Viceroy, sailed in November, 1776, in command of the largest force which up to that time had been sent to the Western Continent. Against his twenty-one thousand men and great fleet the Portuguese had no force, military or naval, strong enough to make a serious resistance.