Siricius was elected Bishop of Rome unanimously, despite attempts by the Antipope Ursinus' to promote himself. He was an active Pope, involved in the administration of the Church, and the handling of various factions and viewpoints within it. He was the first pope to issue decretals, the first of which was the Directa Decretal sent to Himerius of Tarragona. He was the author of two decrees concerning clerical celibacy.
When the Spanish bishop and ascetic Priscillian, accused by his fellow bishops of heresy, was executed by the emperor Magnus Maximus under the charge of magic, Siricus - along with Ambrose of Milan and Martin of Tours - protested against this verdict.
His feast day is 26 November.
Although the Website Religion Facts says that Pope Siricius was the first Bishop of Rome to style himself Pope, more weighty resources say that the title of Pope was from the early third century used for any bishop in the West. It seems that in the East it was used only for the Bishop of Alexandria, but the imperial chancery of Constantinople normally reserved it for the Bishop of Rome. From the sixth century it began to be confined in the West to the Bishop of Rome, a practice that was firmly in place by the eleventh century.
Siricius, again, is one of the Popes presented in various sources as having been the first to bear the title Pontifex Maximus. Others that are said to have been the first to bear the title are Pope Callistus I, Pope Damasus I, Pope Leo I, Pope Gregory I. The Oxford Dictionary of the Christian Church says instead that it was in the fifteenth century (when the Renaissance stirred up new interest in ancient Rome) that "Pontifex Maximus" became a regular title of honour for Popes.