Shortest-reigning popes — With the resignation of Pope Benedict, take a look at history's shortest-reigning popes. You can also view our list of the longest-reigning popes.Pope Urban VII reigned for 13 calendar days in 1590, the shortest papal tenure in history. Hulton Archive/Getty Images Boniface VI — Boniface VI reigned for 16 days in the year 896. Celestine IV — Pope Celestine IV reigned for 17 days and died before consecration in 1241. Hulton Archive/Getty Images Theodore II — Pope Theodore II reigned for 20 days in 897. Hulton Archive/Getty Images Sisinnius — Pope Sisinnius reigned for 21 days in 708. Hulton Archive/Getty Images Marcellus II — Pope Marcellus II reigned for 22 days in 1555. Hulton Archive/Getty Images Damasus II — Pope Damasus II reigned for 24 days in 1048. Hulton Archive/Getty Images Pius III — Pope Pius III reigned for 27 days in 1503. Emory University Leo XI — Pope Leo XI also reigned for 27 days in 1605. Hulton Archive/Getty Images Benedict V — Pope Benedict V was the first to reign for 33 days in 964. Hulton Archive/Getty Images John Paul I — Pope John Paul I also reigned for 33 days before his death in 1978. Keystone/Getty Images Prev Next