Shortest-reigning popes:

• Urban VII (elected in 1590): 13 days
• Boniface VI (896): 16 days
• Celestine IV (1241): 17 days
• Sisinnius (708): 21 days
• Theodore II (897): 21 days
• Marcellus II (1555): 22 days
• Damasus II (1048): 24 days
• Pius III (1503): 27 days
• Leo XI (1605): 27 days
• Benedict V (964): 33 days

1978 is called the “year of three popes”: Pope Paul VI was succeeded by John Paul I, who lived only 33 days. John Paul II succeeded him.