That's So Second Millennium

Portrait fresco of John XXII, 14th century (Collection of the Palais du Roure, Avignon)

 

Here is the big one...the notes this time are nearly entirely from Magisterium AI.

 

John I 523–526

John II 533–535

John III 561–574

John IV 640–642

John V 685–686

John VI 701–705

John VII 705–707

John VIII 872–882

John IX 898–900

John X 914–928

John XI 931–935

John XII 955–964

John XIII 965–972

John XIV 983–984

John XV 985–996

Antipope John XVI 997–998

John XVII 1003

John XVIII 1004–1009

John XIX 1024–1032

John XXI 1276–1277

John XXII 1316–1334

Antipope John XXIII 1410–1415

John XXIII 1958–1963

 

Here is the chronological sequence of the legitimate popes named John, with the notable antipopes inserted where they belong. “Given name” means the name recorded at birth; medieval records are sometimes incomplete, and the reasons for a papal name are often unknown. The numbering is not perfectly continuous because John XVI and John XXIII were also used by antipopes.

• John I (523–526) — Born John. Sent by Theodoric to Constantinople to negotiate for the Ostrogoths; imprisoned on his return and died in captivity. Venerated as a martyr. ¹

• John II (533–535) — Born Mercurius; the first pope known to have changed his name. He likely avoided a name associated with the Roman god Mercury.

• John III (561–574) — Born Catelinus. His long pontificate coincided with the Lombard invasion of Italy; political turmoil left few records of his work. ²

• John IV (640–642) — Born John. Condemned Monothelitism at a Roman synod and used Church funds to ransom captives taken in Dalmatia and Istria.

• John V (685–686) — Born John in Syria; his brief pontificate was largely uneventful.

• John VI (701–705) — Born John, probably in Greece. Protected the English bishop Wilfrid when he appealed to Rome against his deposition.

• John VII (705–707) — Born John in Calabria. His dealings with the Byzantine emperor over the Trullan Council’s canons were notably cautious.

• John VIII (872–882) — Born John. A forceful pope in the politics of the Carolingian empire and the Photian controversy; he was assassinated, the first papal murder reliably documented.

• John IX (898–900) — Born John. Rejected the Cadaver Synod and reaffirmed the validity of ordinations performed by Pope Formosus.

• John X (914–928) — Born John. Helped organize the coalition that defeated Muslim forces at the Garigliano; later imprisoned and suffocated amid Roman political struggles.

• John XI (931–935) — Born John. His mother, Marozia, and later his half-brother Alberic II dominated Roman affairs; John himself was largely confined to the Lateran.

• John XII (955–964) — Born Octavian. He adopted the papal name John, but the reason is not securely known; he crowned Otto I emperor and was later deposed amid a conflict with him. ³

• John XIII (965–972) — Born John. Worked with Otto I to establish church structures in newly Christianized parts of central and eastern Europe.

• John XIV (983–984) — Born Pietro Canepanova. He changed his name on becoming pope; the reason is uncertain. After Otto II’s death, he was imprisoned by the returning antipope Boniface VII and died in captivity. ⁴

• John XV (985–996) — Born John. In 993 he formally canonized Ulrich of Augsburg, an important early precedent for papal canonization.

• Antipope John XVI (997–998) — John Philagathos, a Greek cleric backed by the Roman noble Crescentius and the Byzantine court, opposed Pope Gregory V. He was captured and cruelly mutilated; the number XVI remained in the papal sequence despite his being an antipope. ⁵

• John XVII (1003) — Born Giovanni Sicco. His pontificate lasted only about five months, and little is known of his actions. Some older lists call him John XVI because they omit the antipope.

• John XVIII (1004–1009) — Born Giovanni Fasano. He supported churches in Germany and missionary work in eastern Europe; he reportedly retired to a monastery near the end of his pontificate.

• John XIX (1024–1032) — Born Romano of Tusculum. Brother of Benedict VIII, he was reportedly a layman when elected and received the clerical orders in rapid succession; he crowned Conrad II emperor.

• John XXI (1276–1277) — Born Pedro Hispano, a Portuguese scholar and physician. His pontificate was brief; he died after a building at his residence collapsed. The sequence skips John XX, probably because an earlier list mistakenly counted John XXI as John XX. ⁵

• John XXII (1316–1334) — Born Jacques Duèse. Elected during the Avignon papacy, he governed amid disputes with the Franciscan Spirituals and the Empire. His views on the timing of the beatific vision provoked controversy; shortly before his death, he clarified his position.

• Antipope John XXIII (1410–1415) — Baldassare Cossa, elected during the Western Schism, was recognized by some European powers but is classified as an antipope. The Council of Constance deposed him; he later submitted to the legitimate pope, Martin V, and died a cardinal. ⁵

• John XXIII (1958–1963) — Born Angelo Giuseppe Roncalli. He said he chose John in memory of his father and of the church where he was baptized, and because it was a name borne by many popes. The long-used number had been associated with the antipope Cossa, so Roncalli’s choice also made clear that he regarded Cossa as illegitimate. He convened the Second Vatican Council, opened it in 1962, and issued Pacem in Terris in 1963. Canonized in 2014. ^{6 7 8}

[Compare the list in the Catholic Encyclopedia (1913) for J at https://www.newadvent.org/cathen/j.htm:

John I, Pope Saint - A Tuscan, was warmly received in Constantinople, but upon his return to Rome, was imprisoned by King Theodoric. Pope John died in prison in 526

John II, Pope - A Roman and the son of Projectus; if not born in the second region (Coelimontium) he had at least been a priest of St. Clement's Basilica

John III, Pope - A Roman surnamed Catelinus, d. 13 July, 574

John IV, Pope - A native of Dalmatia, and the son of the scholasticus (advocate) Venantius

John V, Pope - A Syrian whose father was one Cyriacus; when he was born is not known; d. 2 August, 686

John VI, Pope - A Greek, the date of whose birth is unknown; d. 11 January, 705

John VII, Pope - Reigned 705-707

John VIII, Pope - Reigned 872-882

John IX, Pope - Reigned 898-900

John X, Pope - Born at Tossignano, Romagna; enthroned, 914; died at Rome, 928

John XI, Pope - Reigned 931-935

John XII, Pope - Date of birth unknown; reigned 955-64

John XIII, Pope - Date of birth unknown; enthroned on 1 Oct., 965; d. 6 Sept., 972

John XIV, Pope - After the death of Benedict VII, Bishop Peter Campanora of Pavia, earlier imperial chancellor of Italy, was elected pope with the consent of Emperor Otto II, and took the name of John

John XV (XVI), Pope - Enthroned 985; d. April, 996

John XVI (XVII) - Antipope 997-998; d. probably in 1013

John XVII (XVIII), Pope - Date of birth unknown; d. 6 Nov., 1003

John XVIII (XIX), Pope - Successor of John XVII, consecrated Christmas, 1003; d. June, 1009

John XIX (XX), Pope - Enthroned in 1024; d. 1032

John XXI (XX), Pope - Born at Lisbon between 1210 and 1220; enthroned, 1276; died at Viterbo, 20 May, 1277

John XXII, Pope - Born at Cahors in 1249; enthroned, 5 September, 1316; died at Avignon, 4 December, 1334

John XXIII - Antipope (1370-1419)]

On the choice of “John”: John II is the first clear case of a pope replacing his birth name. Later popes did not always explain their choices, so it is safer to say “the reason is unknown” than to assign a motive. John XXIII’s own explanation is unusually well known; his choice also resolved the ambiguity created by the antipope John XXIII of the Western Schism.

[1] Brief History of the Popes of the Catholic Church, Pope 53. https://www.magisterium.com/docs/5c1c0305-3796-4f86-aa16-0976192fe5a0/ref/Pope%2053

[2] Catholic Encyclopedia, Pope John III. https://www.magisterium.com/docs/f2c979a8-871d-4f46-a059-320d3b837a76/ref/Pope%20John%20III

[3] Acta Sanctorum: October, Tomus IX, page971. https://www.magisterium.com/docs/21295254-43a2-4087-bd3f-79da0a582477/ref/page971

[4] Acta Sanctorum: October, Tomus I, page1047. https://www.magisterium.com/docs/1313933b-2f86-4852-8038-23033ac4e84f/ref/page1047

[5] Acta Sanctorum: October, Tomus I, page1048. https://www.magisterium.com/docs/1313933b-2f86-4852-8038-23033ac4e84f/ref/page1048

[6] Brief History of the Popes of the Catholic Church, Pope 261. https://www.magisterium.com/docs/5c1c0305-3796-4f86-aa16-0976192fe5a0/ref/Pope%20261

[7] Encyclopedic Dictionary of the Christian East, John XXIII. https://www.magisterium.com/docs/2cb86786-6b8e-4ddd-b5fe-d1ebaccb869c/ref/John%20XXIII

[8] Biography of Pope John XXIII, page1. https://www.magisterium.com/docs/cbddf34f-3e9c-4649-8d18-36034c36ec2b/ref/page1

You’re right to question that. I overstated the evidence: John XXIII is not shown in the available sources explicitly saying that he chose the number XXIII to reject or disavow Baldassare Cossa.

In his address immediately after accepting the election, Roncalli explained that “John” recalled his father and the parish where he was baptized; he also noted the name’s prominence among popes and its connection with John the Baptist and John the Evangelist. He counted twenty-two earlier popes named John, but did not mention Cossa or say that he was correcting the numbering. ¹

So the careful conclusion is: Cossa’s status as an antipope explains why later Catholic lists do not count him as a legitimate pope, but these sources do not establish that rejecting him was Roncalli’s stated reason for taking “XXIII.” My previous answer presented that inference too confidently.

And yes: the list contains 23 people if both antipopes are included—21 legitimate popes and two antipopes. “John XX” is not a separate pope; John XXI was mistakenly numbered XX in some older lists, a different numbering confusion from Cossa’s claim to XXIII.

[1] Address following Pope John XXIII's acceptance of the supreme mandate (October 28, 1958) - Speech, page1. https://www.magisterium.com/docs/169003f9-b891-4b5e-920e-3402be5d2ab6/ref/page1