When Pope John XXIII is canonized this April, the honor will be long-awaited—and richly deserved. After serving as a model priest and prelate, he became an equally beloved pontiff, convening Vatican II and articulating the timelessness of the Church’s teachings.
Among his most important statements is Ad Petri Cathedram (“To the Chair of Peter”), the opening encyclical of his pontificate. Much less known than Mater et Magistra (1961) and Pacem in Terris (1963)—Pope John’s two great social encyclicals—Ad Petri Cathedram is equally relevant as a significant window into his legacy and a constructive critique of modernity.
Issued on June 29, 1959, the Feast of the Apostles Peter and Paul, Ad Petri Cathedram is about many things—the need for Christian unity under the Holy See, preparations for Vatican II, the role of bishops, the mission of religious, the value of theology, the urgency of world peace, and the necessity of social justice. But if there is one theme reverberating throughout the whole encyclical, it is Pope John’s defense of objective truth and morality—almost fifty years before Pope Benedict famously inveighed against the “dictatorship of relativism.”
The encyclical minces no words. After extending his greetings and apostolic blessings, Pope John comments:
All the evils which poison men and nations and trouble so many hearts have a single cause and a single source: ignorance of the truth—and at times even more than ignorance, a contempt for truth and a reckless rejection of it.
John then affirms that “God gave each of us an intellect capable of attaining natural truth,” but stresses that ordinary people, left to their own devices, “cannot do this easily.” This is why God took mercy on man’s plight, sending his own Son to dwell among us, so that everyone could be led “not only to full and perfect truth, but to virtue and eternal happiness.”
This is followed by a series of dramatic warnings that still concern us today. First, John affirms, as Pope Francis teaches in Evangelii Gaudium, that everyone is “bound to accept the teaching of the Gospel,” for if it is ignored, “the very foundations of truth, goodness, and civilization are endangered.”
He rebukes those “who consciously and wantonly attack known truth,” for those who do so mislead the young and impressionable, an act John denounces as “an altogether despicable business.”
He addresses the press, which has “a serious duty to disseminate, not lies, error, and obscenity, but only the truth,” and to publicize “what is conducive to good and virtuous conduct, not to vice.” He acknowledges that modern communications—radio, television, motion pictures—have the capacity to achieve genuine good, but far too often entice people into “loose morality” and “treacherous error.” Here, the New Evangelization, which John XXIII helped lay the groundwork for, could counter this destructive trend, so that “health will come from a source which has often produced only devastating sickness,” as the encyclical says.
Having criticized earlier skeptics who “contend that the human mind can discover no truth that is certain” and lamented those who are “carried about by every wind of doctrine,” John’s exhortations end with a battle cry against modernity’s “indifference to truth,” especially “that absurd proposition: one religion is just as good as another.”
That becomes clear in the encyclical’s vigorous defense of the family, as God intended it to be. The beauty and unity of the family, declares John, “rises from the holiness and indissolubility of Christian marriage. It is the basis of much of the order, progress, and prosperity of civil society.”
Harmony is achieved when husbands and wives embrace their God-given roles, and when children, in return, honor and obey their parents. The Holy Family is presented as a model to emulate, for “the charity which burned in the household at Nazareth should be an inspiration for every family.”
One cannot help reading these stirring words without thinking about the challenges now facing Christian marriage, or the misguided efforts to redefine it. But long before the campaign to upend the true meaning of marriage, Pope John’s prophetic encyclical described what would happen if marriage was emptied of its supernatural content:
We earnestly pray God to prevent any damage to this valuable, beneficial, and necessary union. The Christian family is a sacred institution. If it totters, if the norms which the divine Redeemer laid down for it are rejected or ignored, then the very foundations of the state tremble; civil society stands betrayed and in peril. Everyone suffers.
Given the force of Ad Petri Cathedram’s warnings—as striking as any of those heard in today’s culture wars—it’s revealing to see how Pope John’s biographers have dealt with it. Many of them, including major writers like Paul Johnson and Thomas Cahill, don’t even mention it. Peter Hebblethwaite does, but complains about its severity, speculating that it may have been ghostwritten.
Even Pope John’s authorized biographers, Mario Benigni and Goffredo Zanchi, struggle with it, wondering why “the prevailing tone is one of condemnation,” and puzzled by John’s “use of uncharacteristically sharp words.”
But there shouldn’t be any great mystery here. As Greg Tobin, Pope John’s most recent biographer, notes, John was a visionary and a reformer, but “deeply traditional in matters of faith and morals.” Ad Petri Cathedram (which Tobin, to his credit, devotes five pages to) reflects the Pope’s commitment to Christianity’s perennial and demanding truths.
For those accustomed to the image of “Good Pope John” as a sugary-sweet pontiff, Ad Petri Cathedram should serve as a healthy corrective; for while John was certainly a joyful man, he was also a serious one, entirely committed to the teachings of the Church.
William Doino Jr. is a contributor to Inside the Vatican magazine, among many other publications, and writes often about religion, history and politics. He contributed an extensive bibliography of works on Pius XII to The Pius War: Responses to the Critics of Pius XII. His previous articles can be found here.