End of the Uruguayan War, with a peace agreement between President Tomás Villalba and rebel leader Venancio Flores, setting the scene for the destructive War of the Triple Alliance.

The Uruguayan War was fought between Uruguay's governing Blanco Party and an alliance consisting of the Empire of Brazil and the Uruguayan Colorado Party, covertly supported by Argentina. Since its independence, Uruguay had been ravaged by intermittent struggles between the Colorado and Blanco factions, each attempting to seize and maintain power in turn. The Colorado leader Venancio Flores launched the Liberating Crusade in 1863, an insurrection aimed at toppling Bernardo Berro, who presided over a Colorado–Blanco coalition (fusionist) government. Flores was aided by Argentina, whose president Bartolomé Mitre provided him with supplies, Argentine volunteers and river transport for troops.

Tomás Villalba y Albin was a Uruguayan politician who served as interim President for five days, at the end of the Uruguayan War, which had begun on 10 August 1864. The war was fought between the governing Blanco Party and the Colorado Party, with the latter supported openly by the Empire of Brazil and covertly by the Argentine president, Bartolomé Mitre. The Uruguayan War was part an almost continuous struggle between the Blanco and Colorado factions since Uruguayan independence in 1828, and was closely linked to a wider regional conflict involving Argentina, Brazil, Paraguay and Uruguay which culminated in the Paraguayan War. The Colorado leader Venancio Flores started a rebellion in 1863 to overthrow Blanco President Bernardo Berro, who led a coalition Colorado–Blanco government. After a series of battles, the Colorados and the Brazilian army controlled most of the country, with the Blancos left in control of just the capital, Montevideo. On March 1, 1864, President Berro stepped down and was replaced by a hard-line senator, Atanasio Aguirre.

Venancio Flores Barrios was a Uruguayan political leader and general who served as President of Uruguay from 1854 to 1855 (interim) and from 1865 to 1868.