In 1906, Pope Pius X published the encyclical 'Vehementer Nos,' marking a definitive response to modernist interpretations of Catholic doctrine and secular ideologies that were gaining traction at the time. The encyclical, written in the context of European states increasingly separating from religious authority and the rise of secularism, outlined the Catholic Church’s stance on a range of issues related to faith, authority, and tradition. Pius X reaffirmed the essential nature of Catholic teaching as being rooted in the divinely revealed truths, which he deemed incompatible with the relativism often published in modern philosophical and theological discourse.

Pope Pius X addressed the encyclical to the bishops and faithful, emphasizing that the integrity of the Catholic faith must remain preserved against the threats posed by modern thought. His strong language was intended as both a pastoral directive and a broader condemnation against elements within society that sought to dilute the Church’s position. The encyclical outlined essential areas such as the inseparability of Church and state, the need for clear adherence to doctrine, and the rejection of ideologies that encourage division and doubt in faith.

The reception of 'Vehementer Nos' was largely positive among traditionalist Catholic circles, reinforcing the authority of the Pope and affirming the necessity of maintaining doctrinal purity in light of growing secularism. This document signaled a pivotal moment in the Church's relationship with the modern world, one that Pope Pius X firmly believed would be crucial for the preservation of Catholic integrity.