15 June – Salaverry-Santa Cruz War: President Santa Cruz and Anselmo Quiroz, representing Peruvian President Luis José de Orbegoso, sign a treaty in La Paz authorizing Bolivia to intervene in Peru.
13 August – Salaverry-Santa Cruz War – Battle of Yanacocha: A united Peru-Bolivian army commanded by Andrés de Santa Cruz defeats Agustín Gamarra at Yanacocha.
16 August – Santa Cruz is elected Constitutional President of the Republic by the parish electoral boards.[2]