Between 1905 and 1916, southern Alberta was home to a multiethnic and multilingual community of Catholics from across Europe and North America. This community was remarkable for its cohesiveness and its accommodation of ethnolinguistic diversity. The present study examines clerical efforts to sustain this community. As Alberta developed according to an Anglo-Protestant model, the Oblates of Mary Immaculate endeavoured to keep laypeople in the Catholic fold by providing them with a familiar linguistic and cultural setting. Oblates mastered foreign languages, adopted unfamiliar liturgy and discipline, recruited specialized clergy, and strove to suppress ethnolinguistic partisanship among the faithful. Although the erection of the Diocese of Calgary (1912) brought these missionaries into direct conflict with episcopal administration, the clergy remained united in its commitment to nurturing the multiethnic and multilingual character of the Catholic community. This study is of particular interest to historians of western Canada and to scholars of pluralistic faith communities.