This dissertation examines the development of political Catholicism in the former Prussian province of Silesia from the 1860s to the 1890s. An important region long neglected by scholars, Silesia featured a mix of ethnic identities (German and Polish) as well as religious identities (Catholic and Protestant); a significant agricultural area, Upper Silesia also became a major industrial center and thus a site of great social change. The provincial clerical movement had reached a nadir in the middle of the 1860s, borne by only a few activists, mostly priests. After German unification, the movement gained greater popular support, the Silesian Center Party achieving the "electoral conquest" of Reichstag mandates in majority-Catholic districts by the middle of the 1870s. Contributing factors included growing hostility toward Catholics in Prussia and the new German Empire, culminating in the church-state conflict known as the Kulturkampf; the establishment of universal manhood suffrage for the Reichstag; mobilization of the parish clergy; as well as the strength of an ultramontane Catholic socio-moral milieu stemming from a mid-century Catholic revival. Silesian elites and masses effectively resisted the Kulturkampf and asserted their ultramontane Catholic identity, strengthening that milieu. From the early 1870s to the early 1890s, the provincial movement was dominated by aristocrats, partially replicating latifundia power relations in the wider provincial society but also featuring more accountability to the electorate than had been the case with traditional notables' politics. The interest in defending the Catholic Church and the ultramontane community prevented major fissures—along socio-economic or ethnic lines, for example—from emerging within the heterogeneous provincial political movement until after the Kulturkampf. When aristocratic Silesian Centrist leaders persisted in supporting an unpopular military expansion measure in 1893, voter opposition played a major role in forcing them to abandon their Reichstag seats. An Upper Silesian Polish nationalist movement was developing at this time too; as of 1893, however, it had not become the major political factor it later would. The retreat of the Silesian Centrist aristocrats served to undercut the aristocratic wing of the Center Party in the national movement and in the national politics of the German Empire.