Chile declares war on Bolivia and Peru

Background. Tensions escalated when Bolivia increased taxes on the Chilean mining company CSFA in February 1878, violating the 1874 Boundary Treaty. Chilean forces occupied Antofagasta on 14 February 1879. Bolivia challenged Chile in December 1878, reviving the tax and relying on its alliance with Peru. Chile dispatched a warship in December 1878, setting the stage for formal declarations of war.

Formal Declarations. War was officially declared between Bolivia and Chile on 1 March 1879. Chilean President Pinto sought and received legislative approval to declare war on Peru, which he executed on 5 April 1879. These declarations formalized the conflict between Chile and the Bolivian-Peruvian alliance, marking the start of the War of the Pacific.

Political Context. The conflict involved complex diplomatic maneuvers. Peruvian mediator Antonio de Lavalle learned of the alliance in March 1879, while Bolivian leader Hilarion Daza was informed in December 1878. Bolivia, lacking a navy, offered letters of marque in March 1879. These actions preceded the formal declarations and highlighted the alliance's operational challenges.