Pope Pius X was head of the Catholic Church from 4 August 1903 to his death. Pius X is known for vigorously opposing modernist interpretations of Catholic doctrine, and for promoting liturgical reforms and Thomist scholastic theology. He initiated the preparation of the 1917 Code of Canon Law, the first comprehensive and systemic work of its kind, which would ultimately be promulgated by his successor. He is venerated as a saint in the Catholic Church.
Pius X was devoted to the Blessed Virgin Mary under the title of Our Lady of Confidence; while his papal encyclical Ad diem illum took on a sense of renewal that was reflected in the motto of his pontificate. He advanced the Liturgical Movement by formulating the principle of participatio actuosa in his motu proprio, Tra le sollecitudini. He encouraged the frequent reception of Holy Communion, and he lowered the age for First Communion, which became a lasting innovation of his papacy.
Like his predecessors, he promoted Thomism as the principal philosophical method to be taught in Catholic institutions.