The French blockaded Buenos Aires port. Members of the Generation of 1837, a group of young intellectuals, conspired against Rosas, established an alliance with Uruguayan caudilloFructuoso Rivera, and obtained French support. Rosas signed a treaty with Britain to abolish the slave trade, ensuring his government British support.
The introduction of barbed wire fencing consolidated private claims to land in the countryside. Development of wool exports created a more diversified economy.
The allied army defeated Rosas at Monte Caseros. Pact of San Nicolás made Urquiza provisional director of the Argentine Confederation. Liberals in the city of Buenos Aires, led by Bartolomé Mitre (1821–1906), rejected the pact and seceded. National capital was moved to Paraná for eight years.
Urquiza became chief executive, and a federal constitution, to which Buenos Aires refused to adhere, was promulgated (May 1). It extended male suffrage and emancipated slaves. The writings of Juan Bautista Alberdi, member of the liberal Generation of 1837, were a major inspiration for the constitution.
Mitre promoted riots against Urquiza in the interior. Urquiza retired after the indecisive Battle at Pavón (Sept. 17, 1861). Mitre assumed the presidency. Constitution of 1853 was amended to allow the government to intervene in the provinces.
Mitre became head of the national government (Aug. 27); he established a national judiciary, treasury, and customs. The British began financing railroads.
