Throughout the history of the Catholic Church, the papacy has been marked not only by spiritual authority but also by political contention. At various times, rival claimants emerged to challenge the legitimacy of reigning pontiffs, often with the backing of powerful secular or ecclesiastical factions. These rival figures are known as antipopes. While they may have occupied the Papal throne or claimed the title of Bishop of Rome, they are not recognised in the official list of legitimate popes. In total, around forty individuals have been designated as antipopes by later Church authorities. The following ten cases offer a glimpse into the complex and often turbulent history of papal succession.

Hippolytus of Rome

Hippolytus of Rome (c. 170–235) is generally considered the first antipope. A prominent theologian and presbyter, he clashed with Pope Callixtus I over theological issues, especially regarding the Church’s treatment of lapsed Christians. Hippolytus considered Callixtus too lenient and allowed himself to be elected by a rigorist faction as a rival bishop of Rome.

He maintained his opposition through the reigns of several popes, until both he and Pope Pontian were exiled to Sardinia during the persecution of Christians under Emperor Maximinus Thrax. Before dying in exile, the two men are said to have reconciled. According to a later account, Hippolytus was martyred by being torn apart by horses, and this would lead him to be considered a saint. He is also considered the patron saint of horses.

Constantine II

In 767, following the death of Pope Paul I, a Roman noble named Toto of Nepi entered Rome with armed supporters and forcibly installed his brother Constantine as pope. However, Constantine was a lay person, so in just one day the church officials made him a deacon, priest, and then bishop before elevating him to the Papacy, no doubt a case of upward mobility within an organization.

Constantine’s rule only lasted a year before some rivals persuaded the King of the Lombards to intervene. The Lombards march on Rome and killed Toto in battle. Constantine was imprisoned, and after a new Pope was elected, they had the antipope excommunicated, blinded, tortured, his tongue cut out, and publicly humiliated before sending him to live the rest of his days in a monastery.

Boniface VII

Franco Ferrucci was a Cardinal Deacon living in Rome during the pontificate of Benedict VI (973–974). Benedict was supported by Holy Roman Emperor Otto the Great but was deeply hated by the people of Rome. Franco was part of a revolt against Benedict, and the Pope was captured and strangled to death. Afterwards, the Romans named Franco the new Pope, taking the name Boniface VII. However, in less than two months, forces from the Holy Roman Emperor came into Italy looking to put down the revolt. Boniface stripped the Papal treasury and fled to the Byzantine Empire.

When Emperor Otto II died in late 983, the anti-Imperial Roman faction again wanted to usurp the current pontiff, John XIV. With Byzantine support, Boniface returned to Rome. John was imprisoned and died a few months later, likely murdered.

Boniface was again sitting on the Papal throne, and for the next year focused his efforts on getting revenge on those who had forced him into exile. In July 985 he suddenly died. It was likely he was the victim of foul-play too, as his body was subsequently dragged through the streets before it was stripped and left under a statue of Marcus Aurelius.

Sylvester III

Our list is really nine antipopes, as officially this person is considered to be a real Pope. However, he more than qualifies to be an antipope. When Pope Benedict IX, considered one of the worst popes in history, was driven from Rome in September 1044, John, bishop of Sabina, was elected to the Papacy (he may have bribed his way into office). He began his rule in January 1045 under the name Sylvester III, but in April of that year, Benedict IX’s forces returned and expelled his rival. Sylvester III returned to Sabina, where he continued to serve as its bishop until 1062.

Although he returned to his bishopric, his papacy was considered illegitimate by many. The Council of Sutri in 1046 deposed him on charges of simony and declared him an antipope. Nonetheless, some modern lists still include Sylvester III as a legitimate pope, reflecting the ambiguity surrounding his claim.

Clement III

Guibert of Ravenna, a staunch ally of Emperor Henry IV, was elected antipope in 1080 during the height of the Investiture Controversy. Pope Gregory VII had excommunicated Henry, and in retaliation, imperial supporters appointed Guibert, who took the name Clement III.

In 1084, Clement III crowned Henry IV as Holy Roman Emperor in Rome. He maintained control of the city on and off for nearly two decades and continued to serve as antipope until his death in 1100. His appointment marked the beginning of a succession of imperial antipopes in open defiance of the Gregorian reform movement.

Gregory VIII

Maurice Bourdin, formerly Archbishop of Braga, became antipope Gregory VIII in 1118 after being appointed by Emperor Henry V in opposition to Pope Callixtus II. His rise followed a falling-out with the papacy, especially over the issue of lay investiture.

Gregory VIII briefly held Rome but was soon expelled. In 1121, he was captured and remained imprisoned in various monasteries until his death in 1137. His defeat marked the effective end of imperial-backed antipopes for the remainder of the 12th century.

Clement VII

The election of Clement VII in 1378 marked the beginning of the Western Schism. After the controversial election of Urban VI, many cardinals claimed they had been coerced and fled to Fondi, where they elected Robert of Geneva as Clement VII. He established his papal court in Avignon and was supported by France, Scotland, Aragon, and Naples, among others.

Clement VII was the antipope in Avignon from 1378 to 1394, but he is perhaps best known for leading a mercenary army against the small city of Cesena in 1377, when he was a papal legate. When the city was captured, Clement ordered the massacre of between 3,000 and 8,000 civilians, an act which earned him the nickname the Butcher of Cesena.

Benedict XIII

Pedro Martínez de Luna was elected in 1394 as the successor to Clement VII in Avignon. Though originally well-regarded for his intellect and reformist views, Benedict XIII became increasingly isolated during his long tenure. Efforts to end the Western Schism through negotiation repeatedly failed due to his intransigence.

By the early 15th century, most European powers withdrew their recognition of him. He retreated to the fortress at Peñíscola in Aragon and continued to claim the papacy until his death in 1423. He also played a role in anti-Jewish legislation in Spain, including supporting the Disputation of Tortosa and other repressive measures.

Alexander V

In 1409, the Council of Pisa attempted to resolve the Western Schism by deposing both Pope Gregory XII and Antipope Benedict XIII. The council elected Petros Philargos, Archbishop of Milan, as a compromise candidate. He took the name Alexander V.

However, neither of the deposed claimants recognised the council’s authority, leading to the existence of three rival popes. Alexander V died in 1410, only months into his pontificate. Rumours circulated that he was poisoned by Cardinal Baldassare Cossa, who succeeded him as Antipope John XXIII, though no definitive evidence exists.

Felix V

Amadeus VIII, Duke of Savoy, was elected antipope in 1439 by the Council of Basel, which had broken with Pope Eugene IV over questions of how much power the Papacy had. Taking the name Felix V, Amadeus represented the last major challenge to papal supremacy from the Church reformers.

His support was limited mainly to parts of Switzerland and Savoy, and after a decade, he resigned in 1449. In a gesture of reconciliation, Pope Nicholas V made him a cardinal. He died two years later, and with him ended the era of officially recognised antipopes.

Want to read more? Check out:

“Stop the Steal!”: Challenging an election, medieval style

The Antipope Who Became a Saint: Forgery, Heresy, and the Power of Manuscripts

Popes through the Looking Glass, or «Ceci n’est pas un pape»

Franchise Conflict: The Tide of Antipopes in the Aftermath of the Eastern Schism

Top Image: Antipope John XXIII (1410–1415), depicted in the Chronicle of the Council of Constance by Ulrich of Richenthal