Antipope

An antipope is a person elected or appointed as pope in opposition to another claimant whom the Roman Catholic Church recognizes as the legitimate pope. Antipopes have arisen through disputed elections, political conflicts, and rival claims to authority.

Papal conclave: The assembly of cardinals that elects a pope under procedures established by the Catholic Church. Disputes over elections to this office have produced rival claimants.
Hippolytus of Rome: A third-century Christian theologian who was elected bishop of Rome in opposition to Callixtus I. He is often identified as the earliest historically documented antipope.
Papal primacy: The doctrine that the bishop of Rome holds supreme authority in the Catholic Church. A rival claimant contests who may exercise this authority.
Pope: The bishop of Rome and head of the Catholic Church. The Roman Catholic Church recognizes one claimant as pope where rival claimants appear.
Western Schism: A division in the Western Church from 1378 to 1417, when rival lines of popes claimed legitimacy. Its competing papal lines made the distinction between pope and antipope especially consequential.
Novatian: A third-century Roman theologian who claimed the bishopric of Rome against Cornelius in 251. His election established one of the earliest documented rival claims to the Roman see.
Papal election: The process by which the cardinal electors choose a new pope. Competing judgments about a particular election can create rival claimants.
Papal schism: A division in which rival claimants or factions dispute the legitimate leadership of the papacy. An antipope is a claimant within a wider conflict over papal legitimacy.
Avignon Papacy: The period from 1309 to 1377 when successive popes resided in Avignon rather than Rome. The papacy's residence in Avignon intensified political tensions preceding the Western Schism.
Felix II: A fourth-century bishop of Rome installed by Emperor Constantius II in opposition to Pope Liberius. His appointment illustrates imperial intervention in a contested succession.

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