EWTN Catholic Q&A
John Paul The Great?
Question from Jeff on 04-03-2005:

Please explain the process whereby the Holy Father would be bestowed with the title John Paul The Great. Could this precede, or must this follow canonization?

God Bless the Holy Father

Answer by Matthew Bunson on 04-08-2005:

The title is used already in an informal way for Pope John Paul II (as seen with Cardinal Sodano's homily earlier this week). The title is not generally bestowed in some formal sense but is attached by common usage and the judgment of history. Three popes bear the title: Leo I (440-461), Gregory I (590-604), and Nicholas I (858-867). Canonization is a separate undertaking.