The study analyzes the ecclesiological controversy between Ultramontane Catholic and Liberal-Gallican sectors on the theological-canonical notion of the Church and the Papacy in mid-19th century Peru. This ideological dispute occurred during the tumultuous years between 1855, at the end of the Liberal Revolution and 1857. The political situation allowed the Ultramontanes to openly expose their ideas in favour of the institutional and theological Romanization of the Church. They met with resistance from the Catholic Liberal-Gallicans sector, whose ideas converged with Liberal and Galician political theories. The controversy moved within the framework of changes in Global Catholicism that reinforced the juridical and doctrinal authority of the Papacy. This theological Romanization was central to the imposition of the Ultramontanists who were the spokesmen for the theological turn directed from Rome. The article analyses the political-theological positions on the Church and the Papacy, the two main themes of the ecclesiological debate, and frames them in the 19th-century changes led by the Papacy, which ended with the entrenchment of Ultramontanism and the Romanizing turn in Peru.