The decree of the Holy Office regarding excommunication of communists is, in the view of canonical experts in Rome, the most far-reaching of modern times. The present action is said to be the first one aimed at reaching individual persons throughout the world.
Pius X (1903-1914) pronounced excommunication against several " modernist " leaders and placed their writings on the Index. He also issued a Syllabus of Errors and wrote the Encyclical Pascendi (1907) which condemns modernism as " the summation of heresies."
All these Papal pronouncements, either because of their general nature or of their individual application. are however, less inclusive and severe than the decree issued by the Holy Office, authorities say.
The same is true, they assert, of the encyclicals of Pope Pius XI on the condition of the Church in Germany, Mit brennender Sorge, issued in 1937. his condemnation of Fascism and of atheistic Corninunism in the encyclical Divini Redemptoris (1937).