While officially the war lasted from 1839 until 1851, it was a part of armed conflicts that started in 1832 and continued until the final military defeat of the Blancos faction in 1904.

[1] After the proclamation of Uruguayan Independence in 1828 a conflict for primacy arose between the leader of the Thirty-Three Orientals Juan Lavalleja and veteran military commander Fructuoso Rivera, who on November 6, 1830, was chosen as the first President of Uruguay.

There Lavalleja organized a new force with the support of Buenos Aires strongman Juan Manuel de Rosas and in March 1834 invaded Uruguay, only to be defeated by Rivera once again.

In order to support Oribe, Lavalleja organized an army in Argentina and moved against Rivera, who was helped by Argentine Unitarians led by General Juan Lavalle.

Unable to deploy land troops, France looked for allied forces to fight Buenos Aires strongman Juan Manuel de Rosas on their behalf.

However, in 1850, both the French and British withdrew after signing a treaty which represented a triumph for Juan Manuel de Rosas and his Federal Party in Argentina.

[4] The government of Montevideo rewarded Brazil's financial and military support at the final stages of the war by signing five treaties in 1851 that provided for perpetual alliance between the two countries.

The treaties also allowed joint navigation on the Rio Uruguay and its tributaries and exempted cattle and salted meat exports from taxes.

Uruguay renounced its territorial claims north of the Río Cuareim, thereby reducing its area to about 176,000 square kilometers, and recognized Brazil's exclusive right of navigation in the Laguna Merin and the Rio Yaguaron, the natural border between both countries.

In 1870, they came to an agreement to define spheres of influence: the Colorados would control Montevideo and the coastal region, the Blancos would rule the hinterland with its agricultural estates.

But the caudillo mentality was difficult to erase from Uruguay and political feuding continued culminating in the Revolution of the Lances (Revolución de las Lanzas) (1870–1872), and later with the uprising of Aparicio Saravia.