* Eulalius is elected antipope of Rome.

* September 4 – Pope Boniface I dies after a 4-year reign that was interrupted for 15 weeks by the faction of the antipope Eulalius.

Antipope Eulalius ( died 423 ) was an antipope who reigned from December 418 to April 419, although elected the day before Pope Boniface I.

The Emperor answered on 3 January 419, recognizing Eulalius as the rightful Bishop of Rome.

The hearing deferred a decision to a synod which was scheduled to meet at Spoleto on 13 June, but commanded both Boniface and Eulalius to stay out of Rome.

" Although Eulalius appeared to be destined to be confirmed to the post, by boldly entering Rome on 18 March — Easter Sunday that year fell on 30 March — and disobeying Imperial orders, he lost the support of the authorities.

Symmachus sent his police to occupy the Lateran, where Eulalius had established himself, and escorted him to a house outside the walls of Rome.

At first the claims of Eulalius as the rightful Pope were recognized by the Emperor Honorius, who sent a letter dated 3 January 419 recognizing him and pardoning the partisans of Boniface provided they left Rome.

He returned to Rome 18 March to celebrate Easter Sunday, but this flouting of the Emperor's orders lost him the support of these two powerful individuals ; the inhabitants of Rome rioted, and the Urban prefect, Aurelius Anicius Symmachus, had his police occupy the Lateran, where Eulalius had made his base, and escort Eulalius out of the city to a house and kept under guard.

Eulalius is said to have subsequently become a bishop under Celestine I According to the Liber Pontificalis, Eulalius was deposed by a synod of 52 bishops and sent to Campania ; then, when Boniface died in 422, the people and clergy of Rome petitioned him to be the new Pope, but Eulalius refused their offer.

An antipope () or anti-pope is a person who, in opposition to the one who is generally seen as the legitimately elected Pope, makes a significantly accepted competing claim to be the Pope, the Bishop of Rome and leader of the Catholic Church.

Hippolytus of Rome ( d. 235 ) is commonly considered to be the earliest antipope, as he headed a separate group within the Church in Rome against Pope Callixtus I. Hippolytus was reconciled to Callixtus's second successor, Pope Pontian, and both he and Pontian are honoured as saints by the Roman Catholic Church with a shared feast day on 13 August.

Callistus was determined to enter Rome which was occupied by the German forces and the antipope Gregory VIII.

Benedict VIII was opposed by an antipope, Gregory VI, who compelled him to flee Rome.

The banishment of the antipope must have been the work of the German party, which were again triumphant in Rome, led by Pandulf the Ironhead.

Until the conclusion of the council of Pavia in 997, Gregory V had a rival in the person of the antipope John XVI ( 997 – 998 ), whom Crescentius II and the nobles of Rome had chosen against the will of the youthful Emperor Otto III, Gregory's cousin.

At the outset, it appeared that the new Pope was willing to negotiate with Henry V, who received the papal embassy at Strasbourg, and withdrew his support from the antipope he had proclaimed at Rome.

Returning to Italy, where antipope Gregory VIII was supported in Rome by imperial forces and Italian allies of the emperor, Calixtus II managed to gain the upper hand amid clear demonstrations of popular support.

At the outset, he had to reckon with the presence of the powerful antipope Clement III in Rome, but a series of well-attended synods held in Rome, Amalfi, Benevento, and Troia supported him in renewed declarations against simony, Investiture Controversy, clerical marriages, and continued opposition to Emperor Henry IV.

Before May was out he was once more in Rome in answer to a summons for the countess Matilda of Tuscany, whose troops held the Leonine City and Trastevere, but when at the end of June the antipope once more gained possession of St. Peter's, Victor again withdrew at once to his Monte Cassino abbey.

He succeeded Pope Pontian, who had been deported from Rome to Sardinia ( along with the antipope Hippolytus ).

* At the death of antipope Clement III, the supporters of the Holy Roman Emperor in Rome choose Theodoric as his successor.

Stephen died before being able to return to Rome, but Hildebrand was successful ; he was then instrumental in overcoming the crisis caused by the Roman aristocracy's election of an antipope, Benedict X, who, thanks also to Agnes's support, was replaced by the Bishop of Florence, Nicholas II.

The death of the antipope Victor IV saw Frederick give his support to a new antipope, Paschal III, but he was soon driven from Rome which once again saw the return of Pope Alexander III in 1165.

* Albert, antipope in Rome.

* Sylvester II is elected antipope in Rome by the supporters of the Holy Emperor.

He becomes an antipope and bishop of Rome.

He drove Gelasius II from Rome in March 1118, pronounced his election null and void, and set up Maurice Bourdin, Archbishop of Braga, as antipope under the name of Gregory VIII.

He at once excommunicated Henry V and the antipope and, under Norman protection, was able to return to Rome in July.

Pope Stephen IX, who was unable to take actual possession of Rome due to the Roman aristocracy's election of an antipope, Benedict X, sent Hildebrand of Sovana and Anselm of Lucca ( respectively, the future Popes Gregory VII and Alexander II ) to Germany to obtain recognition from Agnes.