Honorable Mentions These encyclicals did not have a world-altering impact (at least in the opinion of this author), but are nonetheless immensely important: Aeterni Patris, Leo XIII 1879: This encyclical is credited with helping to revive Thomism in the Church.
Today, one could argue that Aquinas is the single most important Catholic theologian and philosopher, apart from the apostles and the New Testament writers.
This inspired a movement known as distributism, so named because its adherents believe property ownership should be widely distributed, instead of concentrated in the hands of wealthy robber barons or socialist bureaucrats. Providentissimus Deus, Leo XIII 1893: There had been other encyclicals on the Bible before, but none as momentous as this, and probably none since.
As Leo XIII himself wrote, quoting one of Aquinas’ commentators, “Among the Scholastic Doctors, the chief and master of all towers [is] Thomas Aquinas, who, as Cajetan observes, because ‘he most venerated the ancient doctors of the Church, in a certain way seems to have inherited the intellect of all.’” Quas Primas, Pius XI 1925: This encyclical established the Feast of Christ the King, a reminder of the importance of Christ’s kingship on this earth.
‘Christ the King’ became the rallying call of those fighting for the Church in the Cristero War in Mexico.
As one scholar has put it, the encyclical is “the magna carta of modern Catholic biblical studies.” Now this may seem like an arcane matter best left to scholars, but it’s one that affects all of us.
Pope Leo XIII worried that a weak doctrine of inerrancy would diminish reverence for Scripture among all Catholics, causing them to stop believing it in entirely.
At one time, artificial contraception was universally viewed as sinful among Christians.
But, at the 1930 Lambeth conference, the Anglican church reversed its position, prompting Pius XI to issue Casti Connubii, making it clear that the Catholic Church was not about to follow suit, even as many other Protestant denominations did.
They are somewhere in length between a newspaper column and a book. Papal encyclicals have inspired revolutions, changed cultures, and helped topple ideologies and empires. There are some encyclicals, in particular, that have left, it seems, an indelible impact on the world—whether the world of Catholicism, the broader Christian community, or beyond.
Either way, when a pope issues his thoughts on an important matter of faith and morals, the world listens—even if it doesn’t always agree.
Here are seven encyclicals that have changed the world, in one fashion or another, listed in chronological order: Rerum Novarum, Leo XIII 1891: This encyclical is the foundation of all modern Catholic social teaching.
Rerum Novarum sought a Christian basis for property rights in the fact that man is created in the image of God.
Without taking an anti-scientific stance, the pope affirmed an uncompromising doctrine of inerrancy against those who claimed the Bible is only without error in narrow matters of faith and morals.