Longest-reigning popes

Pope Pius IX, the pope with the longest verifiable reign

The longest papal reigns of those whose reign lengths can be determined from contemporary historical data are the following:

1. Saint Peter (c. 30–64/68): c. 34 – c. 38 years (Around 12,000–14,000 days)^[234]
2. Bl. Pius IX (1846–1878): 31 years, 7 months and 23 days (11,560 days)
3. St. John Paul II (1978–2005): 26 years, 5 months and 18 days (9,665 days)
4. Leo XIII (1878–1903): 25 years, 5 months and 1 day (9,281 days)
5. Pius VI (1775–1799): 24 years, 6 months and 15 days (8,962 days)
6. Adrian I (772–795): 23 years, 10 months and 25 days (8,729 days)
7. Pius VII (1800–1823): 23 years, 5 months and 7 days (8,560 days)
8. Alexander III (1159–1181): 21 years, 11 months and 24 days (8,029 days)
9. St. Sylvester I (314–335): 21 years, 11 months and 1 day (8,005 days)
10. St. Leo I (440–461): 21 years, 1 month, and 13 days (7,713 days)

During the Western Schism, Avignon Pope Benedict XIII (1394–1423) ruled for 28 years, 7 months and 12 days, which would place him third in the above list. Since he is regarded as an anti-pope, he is not included there.

Shortest-reigning popes

Pope Urban VII, the shortest-reigning pope

There have been a number of popes whose reign lasted about a month or less. In the following list the number of calendar days includes partial days. Thus, for example, if a pope's reign commenced on 1 August and he died on 2 August, this counts as reigning for two calendar days.

1. Urban VII (15–27 September 1590): reigned for 13 calendar days, died before coronation.
2. Boniface VI (April 896): reigned for 16 calendar days
3. Celestine IV (25 October – 10 November 1241): reigned for 17 calendar days, died before coronation.
4. Theodore II (December 897): reigned for 20 calendar days
5. Sisinnius (15 January – 4 February 708): reigned for 21 calendar days
6. Marcellus II (9 April – 1 May 1555): reigned for 23 calendar days
7. Damasus II (17 July – 9 August 1048): reigned for 24 calendar days
8. Pius III (22 September – 18 October 1503) and Leo XI (1–27 April 1605): both reigned for 27 calendar days
10. Benedict V (22 May – 23 June 964): reigned for 33 calendar days
11. John Paul I (26 August – 28 September 1978): reigned for 34 calendar days