The Ecclesiastical History of Socrates Scholasticus 140Of Gregory Thaumaturgus (the Wonder-Worker).

But since from the likeness of the name, and the title of the books attributed to Gregory, persons are liable to confound very different parties, it is important to notice that Gregory of Pontus is a different person. He was a native of Neocaesarea in Pontus, of greater antiquity than the one above referred to, inasmuch as he was a disciple of Origen. This Gregory's fame was celebrated at Athens, at Berytus, throughout the entire diocese of Pontus, and I might almost add in the whole world. When he had finished his education in the schools of Athens, he went to Berytus to study civil law, where hearing that Origen expounded the Holy Scriptures at Caesarea, he quickly proceeded thither; and after his understanding had been opened to perceive the grandeur of these Divine books, bidding adieu to all further cultivation of the Roman laws, he became thenceforth inseparable from Origen, from whom having acquired a knowledge of the true philosophy, he was recalled soon after by his parents and returned to his own country; and there, while still a layman, he performed many miracles, healing the sick, and casting out devils even by his letters, insomuch that the pagans were no less attracted to the faith by his acts, than by his discourses. Pamphilus Martyr mentions this person in the books which he wrote in defence of Origen; to which there is added a commendatory oration of Gregory's, composed in praise of Origen, when he was under the necessity of leaving him. There were then, to be brief, several Gregories: the first and most ancient was the disciple of Origen; the second was the bishop of Nazianzus; the third was Basil's brother; and there was another Gregory whom the Arians constituted bishop during the exile of Athanasius. But enough has been said respecting them.