The Peruvian Republic was a state that declared itself independent from the Peru–Bolivian Confederation in 1837 under the nominal leadership of Antonio Gutiérrez de la Fuente as Supreme Chief of Peru.

[1] This ephemeral state, although it claimed the entire territory of Peru, barely had control over Arequipa, and saw its end when its troops were cornered by the Confederate Army, and forced to sign the Paucarpata Peace Treaty.

[2] A tariff war soon began between both states,[3] and Luis José de Orbegoso's support of Ramón Freire's failed expedition against Diego Portales worsened the situation.

[4][5] Thus, the Congress of Chile approved the declaration of war on December 26, 1836,[5] claiming that Andrés de Santa Cruz's rule over Peru was illegitimate, and that his influence threatened the integrity of other South American nations, as seen by Orbegoso's support for the attempted invasion of Chile by Freire, specifically pointing out the attempt on Portales.

[5][8] After Blanco Encalada's troops arrived in Valparaíso, he was met with hostile demonstrations and the Chilean government repudiated the treaty of Paucarpata.