Ugo was turned into a Pope by God. It was today, on the 14th of May (That rhymes!). They called him the Pop Pope because he listened to popular music while healing the sick. Of course, the music that was popular back in Ugo's day was utter SHIT and wouldn't be very popular today if people were allowed to hear it. Also, while healing the sick may sound like a nice thing to do, historians have been able to prove that it was Ugo himself who gave them the disease in the first place.
Ugo: Disease-spreading popular healer POP pope.