In Roman Catholicism, a person who tries to take the place of the legitimately elected pope. Some antipopes were elected by factions in doctrinal disagreements, and others were chosen in double elections arbitrated by secular authorities or picked as third candidates in an effort to resolve such disputes. The earliest of the antipopes appeared in the 3rd century. During the Investiture Controversy, Henry IV appointed an antipope, and several more antipopes claimed the papal office over the next 200 years as a result of disputed elections or further struggles with secular rulers. The principal age of the antipope came after the papal court was moved from Rome to Avignon in the 14th century (seeAvignon papacy), an event that led to the Western Schism of 1378–1417. During this era, the popes now considered canonical were elected in Rome, and the antipopes were elected in Avignon.