when Diego de Almagro, returning from Cusco, passed by the Calama shelter, the natives gave him copper horseshoes, which were made using a mysterious Incan technique used by towns conquered by the Incas. The science of such a technique still has yet to be explained, but the presence of such horseshoes further suggests strong Incan influence in Prehispanic times. Hispanic Era Spanish colonization obviously caused some changes; however, the hostile climate impeded establishment of greater control. These changes influenced the control of trade routes that crossed the desert and communication to the port of Cobija with the deposits of Potosí silver and the cattle farms of Salta and Tucumán. In this sense, Calama continued as a main point of provision for commercial routes. In the 18th century, with the Bourbon Reforms. Calama was included in maps of the Captaincy General of Chile in the 18th century, depending from the city of Copiapó. Bolivian Republic Era After Bolivia's Declaration of Independence (6 August 1825), and with gradual changes in the administration of the territory, Calama remained constituted under the Departamento de Litoral (1829), subdivided in the Provincia de Lamar y la Provincia de Atacama (Cobija being the departmental capital). Calama was an important town in the Atacama Province, through which traveled the weekly mail between Cobija and Salta-Potosí, since 1832. In 1840, the provincial capital transferred from Chiuchiu to Calama, increasing the communication boom. The border conflicts between Chile and Bolivia did not reach either Calama or the Atacama Province. The greater dispute concentrated in the central prairie and in the coast, where they began to discover rich silver deposits, saltpeter, and guano. The ambiguity that led to the frontier conflicts was the possession of the central plain and the Atacama coast. The environment was made tense when Chilean troops, under the command of colonel Emilio Sotomayor Baeza, invaded the port of Antofagasta on the morning of February 14, 1879. Later, Bolivia declared war on Chile on March 1. Chilean Republic Era Since that day, the changes in the administration have been very deep. It being part of the administrative center of 2° order in Bolivia, returned as one of 4° order under the Chilean administration (subdelegation). In 1888, under the government of José Manuel Balmaceda, Calama returned as an administrative center of 3° order, inaugurated as the municipality on 13 October. Prior to that, in 1886, Calama was chosen for