URSICINUS, Antipope. - When Pope Liberius died (Sept. 366), while in the church of St. Lawrence in Lucina the deacon Damasus was being canonically elected, in the "basilica Julii" (St. Mary in Trastevere) 7 presbyters and 3 deacons elected the deacon U., who was promptly consecrated by the bishop of Tivoli.
The schism immediately degenerated into civil war, and Rome became the theater of scenes of bloodshed. A group of Damasians in fact besieged the basilica Julii for 3 days and in the end gained the upper hand: there were dead and wounded; U. and the 2 deacons were driven into exile. The presbyters, however, who remained in Rome continued their liturgical assemblies on their own account. To cut off every cause of strife they too were arrested, but their followers snatched them from the police and all together occupied the Basilica Liberiana. The Damasians besieged them once again and succeeded in overpowering them in a scuffle in which 137 people perished. Damasus remained master of the situation, and once calm had returned, in Sept. 367 the exiles were permitted to return. The disorders, however, began again, and the prefect of the city was forced to send U. and his adherents back into exile. A group of fanatics, however, continued to gather in the basilica of St. Agnes on the Via Nomentana; new riots arose from this; the schismatics were then forbidden to gather within a radius of 20 miles from Rome. U., who had meanwhile been relegated to Cologne, obtained permission to reside in Milan, where he joined with the Arians and with Valens of Pettau. Even far from Rome he did not cease to create troubles for Damasus and instigated the converted Jew Isaac to bring a lawsuit against the Pope, who was however found innocent. To prevent him from doing harm, St. Ambrose begged the emperor Gratian by letter to put an end to the machinations of the schism (381). U. died shortly afterward.