An antipope (Latin: antipapa) is a person who claims to be Bishop of Rome and leader of the Roman Catholic Church in opposition to the officially elected pope. Between the 3rd and mid-15th centuries, antipopes were supported by factions within the Church itself and secular rulers. While modern claimants to the papacy still take place, they are rarely given serious consideration by either the public or the Church.
Sometimes it was difficult to distinguish which of two claimants should be called pope and which antipope, as in the case of Pope Leo VIII and Pope Benedict V.