With the dissolution of the Peru-Bolivian Confederation, Peruvian President Agustín Gamarra, made the controversial decision to invade Bolivia and used the political chaos occurring in the Bolivian government as an excuse.

[1] Gamarra had from the beginning supported a union between Peru and Bolivia but preferred it to be completely dominated by the Peruvian government, rather than being a confederation between the two nations.

In the Siege of Tarapacá, Peruvian montoneros, formed by Major Juan Buendía, from Iquique defeated on January 7, 1842 the detachment led by Colonel José María García, who died in the confrontation.

Thus, Bolivian troops vacated Tacna, Arica and Tarapacá in February 1842 and retreated to Moquegua and Puno.

With the battles of Motoni and Orurillo Peru evicted and subsequently initiated the withdrawal of the remaining Bolivian forces that occupied Peruvian territory, again threatening Bolivia to suffer an invasion.