Pope St. Pius X was the only pope since Pope St. Pius V (r. 1566-1572) to have been canonized as a saint of the Church. In 1907 his Holy Office published the famous decree Lamentabili Sane, in which 65 propositions drawn from the works of Modernist writers were condemned, and he himself issued the encyclical Pascendi, in which he outlined the errors of Modernism, described as the "synthesis of all heresies." He suppressed and removed from the seminaries and universities Modernist teachers and in 1910 required that all priests take the Anti-Modernist oath. In his motu proprio Inter Pastoris Officii Sollicitudines (1903), he promoted the restoration of sacred music through the liturgical use of Gregorian chant.