[5] Its leaders were charismatic local caudillos who had great roots and prestige among the rural popular sectors, made up of farm laborers, free gauchos and freedmen.

In 1829, the Unitarian League (Spanish: Liga Unitaria) was created by General José María Paz in order to defeat the Federalists, easily taking power in nine provinces.

The Federalist governments of Buenos Aires, Santa Fe, Entre Ríos and Corrientes, united under the Federal Pact, confronted Paz and his troops on May 31, 1831.

Argentina's Federalist party was primarily led by landowning caudillos, a class of wealthy rural elite who benefited from protectionist trade and tariff policies due to their dependence on agriculture and exports for wealth and influence.

[7] These personalistic leaders governed through patron-client relationships, relying on rural masses for income and, in return, granting a measure of power and influence through association.

These regional strongmen regularly used their patron status to mobilize huge numbers of nomadic gauchos to form both agricultural labor forces and large-scale militias.

Typically divorced from politics in the metropolitan capital of Buenos Aires, caudillos disdained the rising tide of urban liberalism and sought to form their own autonomous fiefdoms in the Argentine interior using the region's history of violence and anarchy to justify swift and brutal repression.

Until unification pacts were signed in order to fight the Unitarians under Juan Manuel de Rosas, caudillos were primarily independent with their influence confined to their regional bases of power.

Following the internecine Argentine Civil Wars, Juan Manuel de Rosas rose to prominence after attaining the position of Governor of Buenos Aires in 1829.

Independently wealthy as a result of massive inherited landholdings and with no serious rivals, Rosas had led the Federalist party as a brigadier general for a number of years before finally consolidating power in Buenos Aires.

Typically illiterate and lacking formal education, the gauchos remain a romanticized figure in the mythology of Argentina and were immortalized in José Hernández' epic poem, Martin Fierro.

[9] Due to Argentina's chronic labor shortages, the caudillos' ability to galvanize the large gaucho population was vital to their economic interests and to their capacity to field armies and militias.

[9] Also in 1829, Juan Manuel de Rosas, the boss of a troop of Gaucho Federalists, became governor of Buenos Aires after defeating General Lavalle, who was then forced into exile.

Following the Revolution of 11 September 1852, the Unitarians of Buenos Aires broke away from the interior provinces after Urquiza nationalized customs receipts and allowed free flow of trade on the Parana and Uruguay rivers.