Pop quiz: What name is most common among popes?

Hint: Today is the feast day ^[1] of the first pope with this name.

A barely-related story: my young son Peter tells me that he wants to be pope someday. I told him that he will have to change his name when he becomes pope, but he wants to keep “Peter” since it is the name of the first pope. I told him that there is a well-known prophecy that the pope who takes the name Peter will be the last pope and that will signal Christ’s return. He seemed to be even more inspired to be the next Pope Peter. Just my luck, my son will be the one who ushers in the apocalypse…