IN October 1959, Father de Nantes suddenly interrupted the regular sequence of the spiritual subjects of his Letters to My Friends to undertake a systematic study of Progressivism, which he immediately denounced as a new heresy, more serious than the worst of the past. Significantly, he entitled this new series, which would eventually include thirty-two letters written from October 1959 to May 1963, The Mystery of the Church and the Antichrist.
This new orientation given to his Letters was the effect of the victorious rise of Progressivism in the Church, corrupting faith and morals which, he said: “made it my duty to undertake against it a struggle neglected by so many others, and moreover delicate and dangerous.”
This painstaking, implacable theological study of an error, the closely convergent theological, moral, liturgical and pastoral implications of which no one at the time had yet clearly and vigorously denounced, was difficult to undertake and carry through.
It is therefore understandable that Father de Nantes had unusual difficulties in beginning to write this study on such a dramatic and overwhelming subject.
What is most noteworthy is that, although this implacable criticism of the Progressivist heresy was published while Father de Nantes was as a parish priest in full communion with his bishop [1959 to 1962], never has the slightest criticism of a doctrinal nature nor any denial on the part of the Magisterium been addressed to him. This was before the great conciliar upheaval, when the destruction, the Progressive novelties were still deprived of any authority, of any legitimacy.
It was Vatican II itself that allowed this subversion of Christianity, conducted from within, to fully manifest itself in all its malice throughout the world. The prophetic lucidity of these thirty-two letters is striking!
THE MYSTERY OF THE CHURCH AND THE ANTICHRIST
1. Within the Church Herself, a New Heresy. Letter 58
2. What Is Progressivism? Lettre 59