On 29 December 1926, Pope Pius XI promulgated the decree of officially condemning a number of books by Charles Maurras, one of the principal directors of the “Action Française” movement in France, and the daily newspaper Action Française, the official organ of the movement. Subsequently, this historical event of European significance brought out heated controversy not only in France but also in England. The controversy between the Vatican and the “Action Française” found its commentary in the editorial page of the Monthly Criterion edited by T. S. Eliot, who was himself involved in the debate in the following pages of the literary review as well as the Church Times, the organ of the Church of England. Nonetheless, this significant event bearing on Eliot appears to have eluded a serious scrutiny of Eliot’s scholars. This study discloses the historical background of the condemnation of the “Action Française” by the Pope, and Eliot’s defense for the movement and Charles Maurras against the Vatican apologists.