Antipope

An antipope is a person who makes a claim to the papacy in opposition to the pope who is recognized by the Catholic Church as the true successor of Saint Peter. Antipopes exercise papal authority within their faction, but their legitimacy is rejected by the Church; their acts are not considered valid sacraments or offices by the Church’s ordinary magisterium, and they are often condemned by later councils or papal decrees. The phenomenon arises when divisions among clergy or secular rulers create rival claims to the papal throne.

Historically, antipopes appeared at various times. Early instances include Hippolytus of Rome (late 2nd–early 3rd century) and Novatian (251–252), whose rival communities viewed them as pope rather than the incumbent. In the late Middle Ages, the most famous episode was the Western Schism (1378–1417), during which rival papal seats operated in Rome and Avignon. Antipopes Clement VII (Avignon) and Benedict XIII ruled in the Avignon line; in 1409 the Council of Pisa elected Alexander V, creating a third line. The Council of Constance (1414–1418) deposed the rival claimants and elected Martin V as pope, ending the Schism and establishing a single line.

Today the term antipope is used primarily in historical contexts. The Catholic Church recognizes only one pope at a time; antipopes are viewed as rival claimants whose authority is not accepted by the Church. In most periods their impact remained confined to their own communities, though the episode significantly affected church politics, governance, and relations with secular powers.