Oath against Modernism

The oath against modernism was issued by Pope Pius X on 1 September 1910 in a motu proprio entitled Sacrorum antistitum. It mandated that "all clergy, pastors, confessors, preachers, religious superiors, and professors in philosophical-theological seminaries" of the Catholic Church swear to it.

The oath continued to be taken until July 1967, when the Congregation for the Doctrine of the Faith rescinded it. It is, however, still taken voluntarily before priestly ordination by some clergy such as the Priestly Fraternity of St. Peter and by certain members of any confraternity: no one is prohibited from taking the oath, nor is anyone compelled to take it.

Pius X had previously defined modernism as a heresy in his encyclicals Pascendi dominici gregis and Lamentabili sane exitu, both of 1907.

Thomas Pègues, O.P. (1866–1936), professor of theology at the Pontifical University of Saint Thomas Aquinas, Angelicum from 1909 to 1921, was one of the prime movers of the anti-modernist movement within the Church, as is expressed in his 1907 Revue Thomiste article "L'hérésie du renouvellement": Puisque c'est en se separant de la scolastique et de saint Thomas que la pensée moderne s'est perdue, notre unique devoir et notre seul moyen de la sauver est de lui rendre, si elle le veut, cette meme doctrine." His 21-volume Catéchisme de la Somme théologique, published in 1919 and translated into English in 1922, went far towards bringing the moral theory of Neo-Thomism to a wider audience.

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