Rivadavia, successor to Las Heras, seeing himself powerless to establish a unitarian constitution, and aware that he could neither carry on the war against the Brazilians nor obtain a peace, resigned power, and Rosas and his colleagues chose Dorrego governor of Buenos Ayres. Dorrego made a treaty of peace with Brazil, through the mediation of England, in 1828, from which year dates the recognition of the Banda Oriental of Uruguay as an independent state, under the triple guaranty of Great Britain, the Argentine Republic, and Brazil. A confederation, based upon voluntary alliance was formed in January, 1831, between the provinces of Buenos Ayres, Corrientes, Entre-Rios, and Santa Fe, which were soon joined by the other provinces. But some of the officers who had commanded in the late i war now began to regard with distrust the tri-umph of federal principles under Dorrego and | the other governors; and the established army of the republic set on foot a counter-revolution, headed by one Lavalle, an officer of some dis-tinction. Lavalle defeated Dorrego and Rosas, and shot the former without a trial.

Rosas, ! however, with Quiroga of La Rioja and Lopez ! of Santa Fe, formed a new league and over-, threw Lavalle, who resigned his post, Rosas being chosen in his place, which he held till 1832. Two governments, the first under Balcarce, and the second under Viamont, now followed each other in the space of a few months, neither being able to maintain itself, as Rosas held the army under his control. After the fall of Viamont, Rosas was reelected governor of Buenos Ayres, a position which placed him at the head of the foreign relations of the country, and gave him a very general control of its internal affairs. His term expired in 1835, when he refused to be again a candidate. Five times the honor was tendered to him, and as often refused. He was then offered the dictatorship for five years, which he accepted, and the appointment was twice renewed. He held the office till 1852, and was the sole and uncontrolled ruler of Buenos Ayres, and practically of the Argentine Republic, during the whole of that time. From 1827 to 1852 there was no meeting of the national congress or constituent assembly. It is difficult to characterize precisely the use which he made of these unlimited powers.

He has been represented as an arbitrary and bloody tyrant, and accused of the treacherous murder of all the friends who placed him in power. He certainly ruled with a strong hand, and was neither slow nor scrupulous in his means of defending or of advancing himself; but he maintained a government under which his country increased in population and material prosperity, notwithstanding continual internal dissensions and foreign wars, and retained a strong and generally triumphant party of friends till the last. With the idea that all the provinces of the former viceroyalty of Buenos Ayres belonged to the Argentine Republic, a contest was long kept up to attempt to bring into it the states of Paraguay and Uruguay. The former, protected in part by its natural position, and more by the policy of isolation and the strong executive power of its singular dictator, Fran-cia, almost entirely escaped foreign conflict. But Brazil had ever in view the conquest of the latter, while the Argentine government saw the importance of that territory, and especially the necessity of checking the ambition of the neighboring monarchy.

The civil dissensions in the Banda Oriental exercised a marked influence on Argentine politics, and the movements headed by Oribe and Rivera served Rosas as a pretext for his intervention in Uruguayan affairs and for the aid given by Brazil to the enemies of the Argentine dictator. Oribe was a partisan if not a creature and tool of Rosas. To him there was opposed a strong faction led by Rivera, a man who had raised himself to influence much in the manner employed by Rosas in Buenos Ayres. The matter came to a war, first of blockades and then of armies, between Oribe supported by Rosas on the one hand, and Rivera sustained by the Argentine exiles in Montevideo, and also by a French fleet, on the other. The intervention of the French was induced by a quarrel which had arisen between a French vice consul and the dictator. The French difficulty was settled by the appointment of a new consul, and in 1840 peace was concluded between the confederation and Montevideo. This peace was not of long duration, and in 1845 Great Britain and France, at the special request of the emperor of Brazil, interfered, on the plea of enforcing the treaties of 1828 and 1840. The allies blockaded Buenos Ayres; seized the Argentine fleet, then engaged in blockading Montevideo, and the island of Martin Garcia, which commands the entrances of the Parana and Uruguay; opened the Parana, which Rosas had closed to vessels bound to Paraguay, and offered convoys as far as Corrientes, where in repeated attempts by the dictator to oppose the passage of the combined fleets the Argentines sustained heavy losses.

This state of things lasted three years, at the end of which period England withdrew (July, 1848), but France continued hostilities six months longer. The rival factions in Uruguay, one of which was supported by Brazil and the other by Rosas, occupied the latter many years, while the opposition party in his own state was gradually becoming too powerful for him. This party, headed by Urquiza, governor of Entre-Rios, was now armed and acting in conjunction with the natural enemy, and at the battle of Monte Caseros, Feb. 3,1852, Rosas was defeated; but, more fortunate than Dorrego had been, he was enabled to escape to England. Vicente Lopez now became provisional governor of the province of Buenos Ayres. But, by a sudden coup d'etat, Urquiza, having the army at his disposal, put himself at the head of the government as dictator, not live months after the deposition of Rosas. The first use of his power was to acknowledge the independence of Paraguay. He also secured the future free navigation of all the rivers flowing into the Plata, a wise measure which still remains in force. But this new assumption of dictatorial power produced immediate irritation.