Pope

=== Shortest-reigning popes ===
[[File:Urban VII.jpg|thumb|upright|[[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.
# [[Pope Urban VII|Urban VII]] (15–27 September 1590): reigned for 13 calendar days, died before [[papal coronation|coronation]].
# [[Pope Boniface VI|Boniface VI]] (April 896): reigned for 16 calendar days
# [[Pope Celestine IV|Celestine IV]] (25 October&nbsp;– 10 November 1241): reigned for 17 calendar days, died before coronation.
# [[Pope Theodore II|Theodore II]] (December 897): reigned for 20 calendar days
# [[Pope Sisinnius|Sisinnius]] (15 January&nbsp;– 4 February 708): reigned for 21 calendar days
# [[Pope Marcellus II|Marcellus II]] (9 April&nbsp;– 1 May 1555): reigned for 23 calendar days
# [[Pope Damasus II|Damasus II]] (17 July&nbsp;– 9 August 1048): reigned for 24 calendar days
# [[Pope Pius III|Pius III]] (22 September&nbsp;– 18 October 1503) and [[Pope Leo XI|Leo XI]] (1–27 April 1605): both reigned for 27 calendar days
# [[Pope Benedict V|Benedict V]] (22 May&nbsp;– 23 June 964): reigned for 33 calendar days
# [[Pope John Paul I|Bl. John Paul I]] (26 August&nbsp;– 28 September 1978): reigned for 34 calendar days

[[Pope-elect Stephen|Stephen]] (23–26 March 752) died of stroke three days after his election, and before his [[consecration]] as a bishop. He is not recognized as a valid pope, but was added to the lists of popes in the 15th century as ''Stephen II'', causing difficulties in enumerating later popes named Stephen. The Holy See's ''Annuario Pontificio'', in its [[list of popes]] and antipopes, attaches a footnote to its mention of Pope Stephen II:

{{blockquote|On the death of [[Pope Zachary|Zachary]] the Roman priest Stephen was elected; but, since four days later he died, before his ''[[episcopal consecration|consecratio]]'', which according to the [[canon law (Catholic Church)|canon law]] of the time was the true commencement of his pontificate, his name is not registered in the ''Liber Pontificalis'' nor in other lists of the popes.<ref>Annuario Pontificio 2012 (Libreria Editrice Vaticana 2012 {{ISBN|978-88-209-8722-0}}), p. 11*</ref>}}

Published every year by the Roman Curia, the ''Annuario Pontificio'' attaches no consecutive numbers to the popes, stating that it is impossible to decide which side represented at various times the legitimate succession, in particular regarding Pope Leo VIII, [[Pope Benedict V]] and some mid-11th-century popes.<ref>''Annuario Pontificio 2012'' (Libreria Editrice Vaticana 2012 {{ISBN|978-88-209-8722-0}}), p. 12*</ref>