The Origins and Precursors of the War of the Pacific

Underlying Causes of the Conflict

As a primary factor, the border problem between Chile and Bolivia emerged. Chile claimed territory up to the 23rd parallel (north of Mejillones), while Bolivia's claim extended to the 26th parallel. Although a difference of three parallels might seem minor, it covered thousands of square miles. Further north, the land encompassing Iquique and Arica belonged to Peru.

The Importance of Nitrate Wealth

The rich nitrate deposits covering the land of Antofagasta, which was then owned by Bolivia, were exploited by foreign capital, primarily Chilean companies. This situation led to significant differences between the two countries until a treaty was signed in 1866. This agreement established that the boundary between Chile and Bolivia would be the 24th parallel, and that the revenue obtained from guano and nitrate mining between the 23rd and 25th parallels would be divided equally between the two nations.

The Failure of the 1874 Agreement

However, the 1866 treaty did not last long. In 1874, a new agreement was signed, which stipulated Chile's resignation of the economic benefits derived from nitrate exploitation in the disputed zone. In return, Bolivia undertook not to raise taxes for 25 years on the Chilean companies already installed in the area.

Immediate Cause: The Tax Violation

During the following years, both Peru and Bolivia underwent important political changes. Mariano Ignacio Prado was elected president of Peru in 1876. Meanwhile, in Bolivia, General Hilarión Daza seized power and, in 1878, passed a law increasing the tax by 10 cents on every quintal (bushel) of saltpeter exported. This decision directly violated the 1874 agreement.

The Chilean government refused to pay the new tax. Daza responded by ordering the confiscation of the nitrate properties held by Chilean companies. Daza knew this action would provoke a war, but he was confident because he had the support of Peru, a country with which Bolivia had signed a secret defensive treaty in 1873.

The Declaration of War (1879)

Against this background, the sequence of events leading to the conflict unfolded rapidly:

• February 12, 1879: Chile broke off diplomatic relations with Bolivia.
• February 14, 1879: On the day the auction of confiscated properties was scheduled to begin, Chilean troops, commanded by Colonel Emilio Sotomayor, landed in Antofagasta to prevent Bolivia's action.
• March 1, 1879: Bolivia, mobilizing an army of 7,000 men, declared war on Chile and confiscated all property held by Chilean citizens in the mineral regions.
• April 5, 1879: After Peru formally recognized the existence of its secret treaty with Bolivia, Chile decided to declare war on both countries.

Thus began the War of the Pacific.