On the death of Dorrego, a remarkable man, Juan Manuel de Rosas, became the Federalist chief.
Rosas gradually concentrated all power in his own hands, and was hailed by the populace as a saviour of the state.
This dictatorship of Rosas continued until 1852.
Buenos Aires was in 1838 blockaded by a French fleet; but Rosas stood firm.
The rule of Rosas was now one of tyranny and almost incessant bloodshed in Buenos Aires, while his partisans, foremost amongst whom was General Ignacio Oribe, endeavoured to exterminate the Unitarians throughout the provinces.
The scene of slaughter was extended to the Banda Oriental by the attempt of Oribe, with the support of Rosas, and of Justo Jose de Urquiza, governor of Entre Rios, to establish himself as president of that republic (see Uruguay), where the existing government was hostile to Rosas and sheltered all political refugees from the country under his despotic rule.
The downfall of Rosas was at last brought about by the instrumentality of Justo Jose de Urquiza, who as governor of Entre Rios, had for many years been one of his strongest supporters.
Rosas met the allies at the head of a body of troops fully equal in numbers to their own, but was crushingly routed, February 3rd, at Monte Caseros, about io m.
But Urquiza was a man of different temperament from Rosas, and when he found that Buenos Aires refused to submit to his authority, he declined to use force.
Subsequently Juan Manuel Rosas, dictator of Buenos Aires, interfered in the intestine quarrels of Uruguay; and Montevideo was besieged by his forces, allied with the native partisans of General Oribe, for nine years (1843-52).
25, 1809) had taken refuge in Tarragona; and Rosas had fallen (Dec. 5, 1808) to the French general Gouvion St Cyr who, having relieved Barcelona, was besieging Gerona.
Several ministries, in which various parties predominated for a time, now governed the country till 1848, during which period the rebellious province of Rio Grande was pacified, more by negotiation than force of arms. In 1848 hostilities were roused with the British government through the neglect shown by the Brazilians in putting in force a treaty for the abolition of the slave trade, which had been concluded as far back as 1826; on the other hand the governor of Buenos Aires, General Rosas, was endeavouring to stir up revolution again in Rio Grande.
The ministry of the Visconde de Olinda in 1849 entered into alliances with the governors of Montevideo, Paraguay and the states of Entre Rios and Corrientes, for the purpose of maintaining the integrity of the republics of Uruguay and Paraguay, which Rosas intended to reunite to Buenos Aires, and the troops of Rosas which besieged Montevideo were forced to capitulate.
Rosas then declared war formally against Brazil.
An army of Correntine, Uruguayan and Brazilian troops, under General Urquiza, assisted by a Brazilian naval squadron, advanced on Buenos Aires, completely routed the forces of Rosas, and crushed for ever the power of that dictator.
The coast, which is partly sandy, partly rocky, extends about 240 m.; its chief harbours are those of the capital, Barcelona, of Matar6, of Rosas and of Tarragona.
It was made the capital of the republic in 1828 and had partially recovered its population and trade when the disastrous struggle with Rosas, dictator of Buenos Aires, broke out and the city was subjected to a nine years' siege (1843-52), the investment being conducted by General Oribe, and the defence by General Paz.
With the rest of the crew, Arago was taken to Rosas, and imprisoned first in a windmill, and afterwards in the fortress of that seaport, until the town fell into the hands of the French, when the prisoners were transferred to Palamos.