List of 10 longest-reigning Popes

The list of 10 longest-reigning Popes in Catholic reckoning, with one extra listing:

St. Peter (30 to 64/67 AD): 34 or 37 years (see notes on St. Peter below)
Pius IX (1846-1878): 31 years and 7 months.
John Paul II (1978-present): 25 years and 5 months or 9283 days as of March 16 2004 - he would pass Pius IX in 2010 if still reigning as Pope; he would be 90 years old in 2010.
Leo XIII (1878-1903): 25 years, 4 months and 29 days (9281 days).
Pope Pius VI (1775-1799): 24 years and 6 months (8962 days).
Adrian I (772-795): 23 years and 10 months.
Pius VII (1800-1823): 23 years and 5 months.
Alexander III (1159-1181): 21 years, 11 months, and 23 days.
St. Silvester I (314-335): 21 years and 11 months.
St. Leo I (440-461): 21 years and 1 month.
Urban VIII (1623-1644): almost 21 years

Notes on St. Peter

St. Peter's place in the list is a matter of some dispute.

The length of St. Peter's reign is given by traditional sources, but their accuracy is uncertain. (In particular, two different death years are proposed.) Traditionally, St. Peter spent 25 years in Rome, but his term is reckoned from the time that Catholics consider Jesus to have given St. Peter his office.

Some non-Catholics dispute St. Peter being in this list (and the list of popes) at all, on the grounds that the papacy as we know it now did not exist until some centuries after Jesus' death. They would therefore consider the occupants of slots 2-11 in the list above to be the ten longest-reigning popes.

Catholics, on the other hand, consider St. Peter to necessarily be the first pope by virtue of his commission by Jesus and especially for being the first Bishop of Rome, regardless of whether he was generally known by, or personally claimed, that title. By Catholic understanding, all later popes reign by virtue of their succession to St. Peter in his office.

For more discussion of disputes about the nature of papacy, and of the evolution of the term pope, see pope.