The present work seeks to understand the contact between Ticuna and Capuchinhos in the region of Alto Solimões in Amazonas. This task is mediated by the emblematic figure of the Capuchin missionary Friar Fidelis de Alviano, who for almost thirty years, had as main activity the catechesis of the Ticuna. Having been assigned to this task, he sought to learn the language from which he developed a grammar, mentioned by several researchers as one of his achievements. A similar fact is related to the publication of the Ethnographic Notes published by the Brazilian Historical and Geographical Institute in 1945. Associated with these achievements are the various missionary exhibitions in which Frei Fidelis presented the Ticuna culture through the artifacts, myths and scenes of daily life . Its trajectory constitutes a kind of representation of what the proclamation of the Catholic faith between the natives of Upper Solimões and, in particular, among the Ticuna people meant. Although marked by the theological understanding of the time that saw through the mission the means to reach civilization, Frei Fidelis, affected by the reality of the Ticuna and the Forest, constitutes a paradox that, among other things, is manifested by changes in behavior and process of cultural and institutional estrangement. His missionary commitment led him to the end of his life to declare the Ticuna as his Indians and to recognize the Upper Solimões as the place of true life.