PRISCILLIANISTS, an heretical sect which rose to some prominence in Spain towards the end of the 4th century and continued to subsist, in varying' numbers, there and in Gaul, until after the middle of the Gth. Its founder was Priscillian, a wealthy and influential layman of considerable reading and ability who had devoted his life to a self-dcnying study of the occult sciences and the deeper problems of philosophy. ln the course of his speculations he came under the influence of two teachers, Elpidius and Agape, who professed to have derived their views froin a certain Marcus, a native of Egypt who had settled in Spain. The creed which Priscillian now formu-lated appears to have combined various features of Gnosti-cism and Manichwism: he seems, for example, to have held the theory of emanations - high in rank among these being the heavenly powers whom be called by the name of the twelve patriarchs, and brought also into close relation with the signs of the zodiac - the doctrine of the cletniurge, the pre-existence of souls, the eternity of the devil, the essen-tial sinfulness of the flesh, the unlawfulness of procreation, and the like. He and his followers retained their con-nexion with the Catholic Church, - insisting, however, on fasting on Sundays, and refusing the bread in the sacra-ment ; but they also held separate meetings in private at which they were accused by- their adversaries (with what truth is not known) of practising magic and indulg-ing in licentious orgies. Many women joined the sect, and among the more prominent of its converts were two bishops, named Instantius and Salvianus. Bishop Hyginus of Cordova, who had been the first to raise the alarm against the new doctrines and practices, himself soon afterwards joined the sect ; but through the exer-tions of Idacius of Emerita the leading Priscillianists, who had failed to appear before the synod of Spanish and Aquitanian bishops to which they had been suminoned, were excommunicated at Saragossa in October 380. The same synod passed certain canons against the heresy, and Ithacius of Ossonuba was charged with the publication of its decisions. Meanwhile, however, Priscillian was made bishop of Avila, and the orthodox party found it necessary to appeal to the emperor (Gratian), who issued an edict threatening the sectarian leaders with banishment. Pris-cillian, Instantius, and Salvianus now passed through Gaul to Italy with the object of enlisting the sympathies of Ambrose of Milan and Pope Damasus, but without result. They succeeded, however, by bribing the pro-consul, it is said, in procuring the withdrawal of Gratian's edict, and the attempted arrest of Ithacius. With the murder of Gratian and accession of Afaximus (383) the aspect of matters ag,ain changed ; Ithacius fled to Troves, and in consequence of his representations a synod was held (38.1) at Bordeaux where Instantius was deposed. Priscillian for his part appealed to the emperor, with the unexpected result that along with six of his companions he was condemned to death and executed at Treves in 385. This first instance of the application of the Theo-dosian law against heretics ca,used a profound sensation throughout the Catholic world ; it had the approval of the synod which met at Treves in the same year, but Ambrose of Milan and :Martin of Tours can claim the glory of having lifted up their voices against it, and of having in some measure stayed the hand of persecution. The heresy, notwithstanding the severe ineasures taken against it, con-tinued to spread in France as well as in Spain ; and the barbarian invasions of the 5th century- appear to have helped its further diffusion. About 444 it attracted the attention of Leo I. at Rome, along with other forms of Maniclmism, and something was done for its repression by a synod held at the pope's instance by, Turribius of Astorga in 446 and by that of Toledo in 447; as an openly pro-fessed creed it wholly disappeared after the second synod of Braga in 563.