The successor of Urquiza was Dr. Santiago Derqui. Trouble soon arose in the new government over the intervention of the federal government in the province of San Juan, because of the assassination of the governor. His successor, who had been selected by the people, was captured by the government troops and shot. Buenos Aires protested at this summary execution, and the Congress resented their protest by refusing admittance to its members. The forces of Buenos Aires under the command of General Mitre defeated the federal army in the battle of Pavon, and Derqui was thus deposed after a brief rule, being compelled to flee from the country. General Bartolomé Mitre, one of the most illustrious men of Argentina, was born in the city of Buenos Aires, on the 26th of June, 1821. His early education was received in his home city, but later he was sent to Montevideo. It was in this city that he imbibed revolutionary doctrines, and took up arms in 1838, in one of the disturbances so numerous in that country. A few years later, when just of legal age, he joined an expedition against Rosas, the dictator. The failure of this expedition caused Mitre to return to Montevideo and turn his fight against that usurper through the columns of the newspapers, a calling which he followed during a large part of his life. At the early age of twenty-three he headed another attack against the tyrant, and was promoted to the rank of lieutenant-colonel. Disagreements with the authorities caused the young officer to leave Montevideo, and he went to the province of Corrientes, where he took part in several engagements against Rosas. The failure of this enterprise caused him to flee to Bolivia, where he spent a number of years in newspaper work and as teacher in the military college. His career also led him to Peru and Chile, in each of which countries he joined in the political struggles, always in behalf of public liberties and generally opposed to the existing governments. His conduct in those countries led him to a number of persecutions, so that he fled from one country to another, generally being received by the people as the champion of modern political ideas. He returned again to Montevideo, where he united with Urquiza, who was at that time a leader of the movement toward liberty from political dictators. He soon separated from that leader, however, becoming an active opponent of his, and to that end founded a newspaper in that city, called _Los Debates_.