A few years later Peru became more prosperous through the development of her rich mineral resources and began pressing for a settlement of the question. To the arbitration proposition presented by Peru Chile maintained that there was nothing to arbitrate. In 1905 Peru presented her side of the question in the form of a written protest against certain proposed industrial improvements in the disputed territory. The reply of the Chilean government to the arguments offered in the protest was an able statement of the case, which left little doubt in the minds of those familiar with the subject that it was Chile’s intention to retain possession of the territory in question. In June 1905 diplomatic relations between the two republics were resumed, and Peru sent Don Manuel Alvarez Calderon as Envoy Extraordinary and Minister Plenipotentiary to Santiago, where he was warmly received by President Riesco and his Cabinet Ministers. In his address in presenting his credentials to the President of Chile, on November 4, 1905, Señor Calderon stated that he was charged with the task of settling outstanding questions in conformity with treaty stipulations, meaning, it was understood, the Tacna and Arica question. In February 1906 the Chilean government named Don Rafael Balmaceda as Envoy Extraordinary and Minister Plenipotentiary to Peru. The more amicable relations resulting from the appointment of diplomatic representatives continued until 1909 when Chile proposed the taking of the plebiscite on certain bases which were then considered unacceptable by Peru, and diplomatic relations were again broken off by the latter country. The main points at issue in this instance involved the questions of who were to constitute the voters, who should preside at the proceedings of the plebiscite, and at what date the election to secure an expression of the residents of the disputed territory should take place. During the year 1912 an effort was made on the part of the respective governments to agree upon terms acceptable to both countries for the celebration of the plebiscite provided for in the treaty of Ancon, to determine the nationality of the provinces of Tacna and Arica, and the following general agreement was reached: