Since 1900, it’s been unavailable but before that, “Christ’s foreskin was one of the most popular relics in Christendom” (David Farley, AN Irreverent Curiosity: In Search of the Church’s Strangest Relic in Italy’s Oddest Town ) Catherine of Siena said she wore the foreskin as a wedding ring, being a bride of Christ. Bridget of Sweden had a vision in which the Virgin Mary assured her that the relic was for real. Popes from the ninth through the eighteen century wrote about it, and Bonaventure entered a theological debate centering on the foreskin. Strendahl visited Calcata to see it, Joyce wrote about it in Ulysses , and it shows up in Eco’s Baudolino .

In 1900, Pius XIII cracked down. According to Farley, “anyone who talked about, wrote about, or commented on the Holy Foreskin would face excommunication. The Church feared the relic was being sought out simply as an ‘irreverent curiosity.’ The people of Calcata could still hold their New Year’s Day procession with the relic, but that would be the only time of year it would be on display - and it would have to be from a distance and without commentary.” From that point, it was no longer to be named as a prepuzio but simply a reliquia or a cosa (“thing”).

Four centuries on, Calvin, who pointed out that Europe boasts multiple foreskin relics, was finally vindicated.