A fact that strengthened the Peruvian-U.S. relations during first half of the 19th century was the discovery of “guano” (a substance composed chiefly of the excrement of seafowl and used as a fertilizer) in Peru, product that – given its properties and agricultural virtues – attracted hundreds of boats from the United States to the Chincha Islands (Clayton, p. 83). As a positive consequence, the level of Peruvian exports to the American market was significantly increased. Thanks to the business of operation and sale of the “guano”, the revenues of the Peruvian Government also increased in significant manner.
Later on, under the Administration of Marshal Castilla (President in 1845-51 and 1854-62), our country gained an increasing economic prosperity and began a process of consolidation and modernization of the Peruvian State. This situation was favorable in the strengthening of the relations between Peru and the United States. The guano business was consolidated and it was supplied to the agricultural fields in the United States, during the second half of the 19th century.
During the period of the Chargé d’Affaires, James C. Pickett, both countries signed, in 1851, the first Treaty of Friendship, Commerce and Navigation, which included a clause of most favored nation. This Treaty was in force during 12 years and marked the beginning of a more fluid and constructive relation. When Chargé d’Affaires Pickett concluded his mission, he was replaced by John Randolph Clay.
The relations between Peru and the United States of America were not absent of differences. One controversy was on the Amazon river in 1854, where the Government of Peru confiscated U.S. boats carrying guano in 1858. As a consequence to this situation, in 1860 the diplomatic relations were temporarily interrupted, and reestablished in 1861. A year later an Agreement of Claims was signed as well as two Additional Agreements – in 1863 and 1868 – that ended these controversies.
During the time of the conflict with Spain, the United States offered to mediate in the dispute, but Spain rejected the U.S. offer because it preferred a bilateral solution. When war was declared, the Peruvian Government invited the United States to join the Peruvian-Chilean alliance. The U.S. Government, nevertheless, reaffirmed its neutral policy, although it repeatedly maintained its efforts as a mediator.
In September of 1870, Peru and the United States replaced the Treaty of Commerce and Navigation of 1851, with one that differed from the previous one in several aspects. In August of 1887 a new Treaty of Friendship, Commerce and Navigation, was signed, and later ratified in October of 1888. This agreement, together with other instruments subscribed between both countries, elevated the level of the Peruvian-U.S. relations.