a synod at Zaragoza in 380. Though summoned, the Priscillianists refused to appear. The synod pronounced sentence of excommunication against the four leaders, Instantius, Salvianus, Helpidius and Priscillian.

Ithacius was chosen to enforce the synod's decrees, but he failed to bring the heretics to terms. In defiance Priscillian was ordained to the priesthood and appointed Bishop of Avila. Ithacius then appealed to the imperial authorities. The emperor Gratian