In May 1941, as tensions at the Ecuadorian-Peruvian border mounted and war was imminent, the governments of the United States, Brazil, and Argentina offered their services in aiding in the mediation of the dispute. Their efforts failed to prevent the outbreak of hostilities on July 23, 1941, but the diplomatic intervention led to a definitive cease-fire being put into place on July 31. Despite this, limited
skirmishes continued to occur through the months of August and September in the Ecuadorian provinces of
El Oro and
Loja, as well as in the Amazonian lands. On October 2, with military observers from the three mediating countries serving as witnesses, Ecuador and Peru signed the
Talara Accord, which created a demilitarized zone inside the provinces of El Oro and Loja, pending the signing of a definitive
peace treaty. Diplomatic efforts continued, with the mediating countries being joined by Chile. On January 29, 1942, on the final day of the third Pan-American Summit, held in
Rio de Janeiro, the foreign ministers of Ecuador and Peru,
Julio Tobar Donoso and
Alfredo Solf y Muro, signed a "Protocol of Peace, Friendship, and Boundaries", known as the
Rio de Janeiro Protocol. The observers from the United States, Brazil, Argentina, and Chile co-signed the document, becoming "Guarantors of the Protocol". The Rio Protocol was subsequently ratified by each country's congress on February 26, 1942. By the terms of the Protocol, Ecuador agreed to withdraw its long-standing claim for rights to direct land access to the
Marañon and
Amazon rivers; Peru agreed to withdraw Peruvian military forces from Ecuadorian territory. An area of of hitherto disputed territory in the Maynas region of the Amazonian basin was awarded to Peru. The
status quo line defined in the 1936 Lima Accord was used as the basis for the definitive border line; the previous border recognized current possessions, but not
sovereignty. Relative to the 1936 line, Ecuador ceded 18,552 km2 of previously possessed territory to Peru, while Peru ceded 5,072 km2 of previously possessed territory to Ecuador. The intended goal of the Rio Protocol was not fulfilled until the signing of the
Itamaraty Peace Declaration in 1995. Between the signing of the two treaties, the
Paquisha Incident and the
Cenepa War rekindled the dispute. == References ==