Sylvester IV was a claimant to the papacy
from 1105 to 1111. Members of the Roman
aristocracy, with the support of the future
Emperor Henry V set up another Antipope to
replace Pope Paschal II, electing Maginulfo, the
Archpriest of St. Angelo in Peschiera, while
Paschal was outside of Rome. After his election,
Maginulfo took the papal name of Sylvester IV
and was consecrated in the Church of St. Maria
Rotonda (the Pantheon) and was enthroned in the
Lateran on November 18, 1105.
When Pope Paschal II returned to Rome the next day, Antipope Sylvester IV left for Tivoli and finally settled in Osimo, Province of Ancona, under the protection of Count Guarniero di Ancona. On April 11, 1105, Pope Paschal II and Emperor Henry IV reached an agreement about the investiture of Catholic bishops. Then the Emperor, who had used Sylvester to exercise pressure on Paschal, made Sylvester abandon his claim to the office of Pope and submit to Paschal. He was allowed to live out the rest of his life in Ancona with his patron, Duke Guarniero.
