Maginulfo is elected Antipope Sylvester IV in opposition to Pope Paschal II.

An antipope 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.

Sylvester IV, born Maginulf, was a claimant to the Papacy from 1105 to 1111 in opposition to Paschal II. A priest before his election, he was probably a native of Rome. He had the backing of the Roman militia and initially of the Holy Roman Emperor, Henry IV, who later forced him to abdicate. Today he is regarded as an antipope.

Pope Paschal II, born Raniero Raineri di Bleda, was head of the Catholic Church and ruler of the Papal States from 13 August 1099 to his death in 1118. A monk of the Abbey of Cluny, he was created the cardinal-priest of San Clemente by Pope Gregory VII (1073–85) in 1073. He was consecrated as pope in succession to Pope Urban II (1088–99) on 19 August 1099. His reign of almost twenty years was exceptionally long for a medieval pope.

November 18 is the 322nd day of the year in the Gregorian calendar; 43 days remain until the end of the year.