SILVESTER III, ANTIPOPE. — John, bishop of Sabina. Little is known about him, except that in order to put an end to the discontent aroused in Rome by the authoritarian Benedict IX, he was elected by the Romans in January 1045 as his opponent; but his tenure was brief.
In March, the brothers of Benedict IX forced him to leave and to restore the fugitive pontiff to the Lateran Palace. In December 1046, under pressure from Henry III, the situation was clarified at the Synod of Sutri, which deposed Sylvester III.
BIBL.: A. Fliche, La Réforme grégorienne, I, Louvain-Paris 1924, p. 108; J. Gay, Les papes du XIe siècle et la chrétienté, Paris 1926; Fliche - Martin - Frutaz, VII, nn. 96-97, 100.