Many of the officers of the army which had been victorious at Ituzaingo were dissatisfied with the triumph of Dorrego at Buenos Aires. They belonged to the unitarian party, and they were anxious themselves to usurp the places of the various caudillos. The first division that reached Buenos Aires after the signing of the preliminary peace with Brazil raised the standard of rebellion in the city itself. General Lavalle declared himself Governor, while Dorrego fled to the interior, only to be pursued, captured, and shot, without the form of trial, by Lavalle's personal order. This began the fiercest and bloodiest civil war which ever desolated the Argentine. The gauchos of the southern provinces rose _en masse_ to fight the unitarian regulars, while the generals of the latter began a series of campaigns against all the federalist provincial governments and caudillos. General Paz advanced on Cordoba to give battle to Bustos, while Lavalle's forces invaded Santa Fe. Rosas, the chief of southern Buenos Aires, had rallied the federalists of that province. He himself joined Lopez, the caudillo of Santa Fe, while he left behind a considerable force of his gauchos to threaten the city from the south. Lavalle sent some of his best regiments against the latter body, but to his surprise his veterans were completely cut to pieces by the fierce riders of the plains. He himself had to retreat to Buenos Aires, while Rosas and Lopez defeated him under the very walls of the city. These victories made the Buenos Aires federalist leader, Juan Manuel Rosas, the chief figure in Argentine affairs. Thenceforth, for more than twenty years, he was the absolute dictator and tyrant of Buenos Aires. The most bitterly hated man in Argentine history, probably no other leader had as profound an influence in preparing the Argentine nation for the consolidation which was so shortly to follow his own fall from power. His personal characteristics and his public career are equally interesting. The scion of a wealthy Buenos Aires family, from his childhood he devoted himself to cattle-raising on the vast family estates of the southern pampas. He became the model and idol of the gauchos. By the time he was twenty-five, he was the acknowledged king of the southern pampas, with a thousand hard-riding, half-savage horsemen obeying his orders. In 1820 he and his regiment were chief factors in the revolution that placed General Rodriguez in power at Buenos Aires. Through the more peaceful years that followed, his power grew until he was the acknowledged head of the country people of Buenos Aires province and their champion against the city. He had been fairly well educated, his information was wide, and his intellectual abilities were of a high order. But he thoroughly identified his tastes and prejudices with those of his rude followers, and in politics he was fiercely unitarian. The victories of 1829 over Lavalle placed him in supreme power at Buenos