In 1852, Rosas was deposed, and a constitutional convention was summoned. This constitution, still in force, established a national federal government, with the office of the President. The term was fixed as six years, with no possibility of reelection. The first elected president under the constitution was Justo José de Urquiza, but Buenos Aires seceded from the Argentine Confederation as the State of Buenos Aires. Bartolomé Mitre was the first president of the unified country, when Buenos Aires rejoined the Confederation. Thus, Rivadavia, Urquiza, and Mitre are considered the first presidents of Argentina by different historians: Rivadavia for being the first one to use the title, Urquiza for being the first one to rule under the 1853 constitution, and Mitre for being the first president of Argentina under its current national limits.