“... Papal abdication that was voluntary?”
I found five resignations: Gregory XII (1406-1415), St. Celestine V (1294-1294), Benedict IX (1032-1044), St. Pontian (230-235 A.D.) and a possible /conjectured St. Clement (88-97 A.D.). The only Pope that resigned without political pressures/other issues at hand was St. Celestine V. So... sounds like one before. (I had to do some research. My 12 years of Catholic School didn’t quite prepare me for this!)
Mine neither!