300 priests in the state of Pennsylvania alone over seven decades. In late August, Archbishop Carlo Maria Viganò, a former papal diplomat, published a letter accusing Pope Francis of knowing about McCarrick’s sexual abuses for years and helping to cover them up. Viganò concluded by calling on the pope to resign.

The Viganò letter, and the scandal itself, have sent shockwaves through a foundation that was already cracked. The church is bitterly divided between progressive and conservative wings. This split is particularly pronounced in the United States, where highly mobilized, neo-traditionalist Catholics took up Vigano’s call for Francis’ resignation.

In desperate need of institutional reform and facing growing political, theological, and geopolitical rifts, the church has not experienced so great a crisis since the Protestant Reformation. Unlike that of the sixteenth century, the current situation probably won’t result in a schism or the establishment of new churches. But to understand the magnitude and complexity of what is now taking place, we have to look that far back, and to so significant a rupture.