The Ecclesiastical History Of Theodoret by Theodoret
Chapter XXX.--Of the church of the Goths.
It was perceived by John that the Scythians were involved in the Arian net; he therefore devised counter contrivances and discovered a means of winning them over. Appointing presbyters and deacons and readers of the divine oracles who spoke the Scythian tongue, he assigned a church to them, and by their means won many from their error. He used frequently himself to visit it and preach there, using an interpreter who was skilled in both languages, and he got other good speakers to do the same. This was his constant practice in the city, and many of those who had been deceived he rescued by pointing out to them the truth of the apostolic preaching.