Saint Pope Pius X (Ecclesiastical Latin: Pius PP. X) (2 June 1835 – 20 August 1914), born Giuseppe Melchiorre Sarto, was the 257th Pope of the Catholic Church, serving from 1903 to 1914. He was the first pope since Pope Pius V to be canonized. Pius X rejected modernist interpretations of Catholic doctrine, promoting traditional devotional practices and orthodox theology. His most important reform was to publish the first Code of Canon Law, which collected the laws of the Church into one volume for the first time. He was a pastoral pope, encouraging personal piety and a lifestyle reflecting Christian values. He was born in the town of Riese, which would later append "Pio X" (Pius X's name in Italian) to the town's name.

Pius was particularly devoted to Mary; his encyclical Ad Diem Illum expresses his desire through Mary to renew all things in Christ, which he had defined as his motto in his first encyclical. Pius believed that there is no surer or more direct road than by the Virgin Mary to achieve this goal. Pius X was the only Pope in the 20th century with extensive pastoral experience at the parish level,^{[citation needed]} and pastoral concerns permeated his papacy; he favoured the use of the vernacular in catechesis. Frequent communion was a lasting innovation of his papacy. Pius X, like Pope Pius IX, was considered by some to be too outspoken or brusque. His direct style and condemnations did not gain him much support in the aristocratic societies of pre–World War I Europe.