The pontificate of Siricius was in no way as violent or disturbing as that of his predecessor, Pope Damasus. A native of Rome, Siricius had been active in the Church since he was a young man. He started as a lector, was ordained a deacon during the pontificate of Liberius, and served in some capacity under Damasus. After that pope's death, Siricius was unanimously elected by the clergy and laity of Rome in December, 384, to replace the fallen pope. The only bad part was that Ursinus, the rival of Damasus, who had been banned to Milan, tried to maintain his claims. The emperor, Valentinian III, quickly wrote a letter to Rome, consenting to the election and praising Siricius' piety. The man's reputation preceeded him.
Siricius held the office of Bishop of Rome until November 26, 399. His reign was full of challenges, battling heresies and building the Church.
His first challenge was addressed to Bishop Himerius of Tarragona, Spain, who had written the newly elected pope fifteen questions on baptism, penance, church discipline, etc. His perception of his responsibilities, Siricius addressed thus to Bishop Himerius: "And since it is necessary for us to succeed to the labors and responsibilities of him whom, through the grace of God, we succeeded in honor … For in view of our office there is no freedom for us, on whom a zeal for the Christian religion is incumbent greater than all others, to dissimulate or be silent. We bear the burdens of all who are oppressed, or rather the blessed apostle Peter, who in all things protects and preserves us, the heirs, as we trust, of his administration, bears them in us.” He then proceeded to explain Church canons, including his command for priestly celibacy. His letter to Bishop Himerius is the first extant decretal we have. A decretal is a legally binding instruction on Church practice and discipline.
He followed up with a synod in 386 which reaffirmed Church discipline in nine canons. After that, he sent letters to all non attending bishops to inform them of the disciplines established and instructed them to act in accordance with the canons. Then he sent letters to various churches detailing the need to elect worthy bishops and priests. At all times, Siricius showed his awareness of his position and the duty to pastoral care.
There were several heresies that Siricius had to deal with during his almost 15 year pontificate. One was the heresy preached by the Roman monk Jovinian who preached that Mary and Joseph went on to have more children, that fasting and good works were not necessary and that celibacy was not highly merited. A synod in 390-392 condemned Jovinian and his followers. And just to make sure it was well understood, St. Ambrose, friend of Siricius and Bishop of Milan, held a second synod which came to the same conclusion.
The second heresy was that of Bishop Bonosus or Sardica (now Sophia, Bulgaria). He preached that Mary was not always a virgin, similar to Jovinian's view. Siricius left the final decision to the Bishop of Thessalonica, which was a wise choice. The pope did not look like he was controlling all, and the bishop straightened it all.
The Priscillian heresy, which was primarily in Spain, was similar to the gnostics in that they thought some people could attain bodily, spiritual and mental perfection. Those of "wisdom and light" could get there. They practiced receiving the Eucharist and consuming it later, or fasting on Sunday or meditating at home rather than attending church. These practices were contrary to Christianity as practiced by most. Priscillian was condemned and executed but his teachings lived on. Siricius was not in favor of the execution, but he was not yet pope at the time. He pitied the mislead and sent letters to the Spanish bishops to explain the circumstances under which the heretics could be brought back to communion with the Church.
It is said that Siricius wrote against the Manicheans in Rome, but he did not take any action against them.
Aside from handling all these challenges, Siricius had the Church of St. Paul Outside the Walls built. The church burned in the 1820s, but there is one column from the first church which was saved. It has an inscription with Siricius' dedication on it.
Siricius died at the age of 65 and was buried in the cemetery of Priscilla on the Via Salaria.