In April of 1879, Chilean army and naval forces
invaded the province of Atacama and occupied Antofagasta. Bolivia appealed
to Peru who responded in defense of her neighbor and ally. Thus the
war was now expanded to the three nations. However, Bolivia and Peru were poorly
prepared to confront the superior military
and naval forces of Chile, and the war
went badly for them, especially after the
defeat of the Peruvian fleet in the Battle
of Angamos on October 8, 1879.