Pope Peter

The papacy is no stranger to controversy.

In many ways it's Catholicism's defining doctrine—but also its most divisive. From medieval pontiffs who acted like princes to a modern pope whose every casual statement sets off a social-media firestorm, there has been plenty for non-Catholics to criticize and for the faithful to feel anxious about.

We profess that Jesus made St. Peter the visible head of his Church on earth and that his successors throughout the ages are guided by the Holy Spirit to...