Siricius, pope from 384 to 398, was a firm defender of the orthodox faith and a zealous promoter of the power of the Church through the exercise of a rigid discipline. He condemned the monk Jovinian and bishop Bonosus of Sardica (q.v.) as heretics, and zealously prosecuted the suppression of the Manichaean and Priscillianist heresies at Rome. By carefully making use of circumstances he succeeded in attaching Eastern Illyria to the see of Rome, and induced the bishop of Thessalonica to acknowledge himself the vicar of Rome for that province. He was the first to make celibacy a law of the Church, and furnished in his Epist. ad Himerium Episc. Turraconensem the earliest decretal to this end. Epistles from his pen are still extant. See Petr. Conistant. Epist. Rom. Pontificum in Gieseler's Lehsrbuch d. Kirchengeschichte, 1, 2; Bonn, p. 333, and comp. p. 199, 276. See Herzog, Real-Encyklop. s.v.