List of 10 longest-reigning Popes

1. St. Peter (30 to 64/67 AD): 34 or 37 years, of which, according to tradition, he spent 25 in Rome. (Peter was not however known as pope in his lifetime)
2. Pius IX (1846-1878): 31 years and 7 months.
3. Leo XIII (1878-1903): 25 years and 5 months (9281 days).
4. John Paul II (1978-present): 25 years or 9131 days as of 16 October 2003, would pass Leo XIII on 14 March 2004 if still reigning as Pope.
5. Pope Pius VI (1775-1799): 24 years and 6 months (8962 days).
6. Adrian I (772-795): 23 years and 10 months.
7. Pius VII (1800-1823): 23 years and 5 months.
8. Alexander III (1159-1181): 21 years, 11 months, and 23 days.
9. St. Silvester I (314-335): 21 years and 11 months.
10. St. Leo I (440-461): 21 years and 1 month.