The Polish thinker Andrzej Towiański (1799-1878) promoted a heterodox Catholic doctrine that was diffused, and survived thanks to his disciples, between the first decades of the nineteenth century and the middle of the twentieth century. Towiański's thought, focused on a nationalist messianic approach and a reformation of the Roman Catholic Church, was able to attract several people mostly among the Polish, French, and Italian intellectual, military, religious, and political classes. Towianism was an elitist phenomenon that involved a restricted number of individuals. Nonetheless, it spread from Eastern to Western and Mediterranean Europe and was identified as a menace by political and religious institutions. The Towianists, imbued by an eschatological tension, wanted to gather disciples and spread their Master's doctrine. On the other hand, they had to deal with the opposition of various States and the Church. Two main research questions drive this study: 1) Why was Towianism perceived as a peril to the State and ecclesiastical institutions? 2) Given the political opposition suffered, how did the Towianists act to overcome the institutional repression? Through the study of published and unpublished sources, this contribution investigates both the reaction of a hegemonic institutional power to a religious minority and the latter's attempt to survive and continue its social and religious endeavours amidst the epoch of Romantic nationalism, the establishment of nation-States, and the progressive dissolution of the temporal power of the Roman Catholic Church.