Pacelli took the same papal name as his predecessor, a title used exclusively by Italian Popes.

The practice of choosing a papal name started in the sixth century.

The first papal name to be repeated was Pope Sixtus.

A papal name is the regnal name taken by a pope.

Since 1555, every pope has taken a papal name.

I believe he has already chosen his papal name: Adrian II, they tell me.

He was the last pope to use a papal name that had not been previously used until the election of Pope Francis in 2013.

If a papal name is used for the first time, the announcement may or may not use the numeral the first.

The case and inclusion or exclusion of numeral for the papal names are noted.

John has been the papal name of several Coptic Popes.