The Ecclesiastical History of Socrates Scholasticus

In the meanwhile Valens, making his residence at Antioch, was wholly undisturbed by foreign wars; for the barbarians on every side restrained themselves within their own boundaries. Nevertheless, he himself waged a most cruel war against those who maintained the ‘homoousian’ doctrine, inflicting on them more grievous punishments every day; until the philosopher Themistius by his Appealing Oration somewhat moderated his severity. In this speech he tells the emperor, ‘That he ought not to be surprised at the difference of judgment on religious questions existing among Christians; inasmuch as that discrepancy was trifling when compared with the multitude of conflicting opinions current among the heathen; for these amount to above three hundred; that dissension indeed was an inevitable consequence of this disagreement; but that God would be the more glorified by a diversity of sentiment, and the greatness of his majesty be more venerated, from the fact of its not being easy to have a knowledge of Him.’ The philosopher having said these and similar things, the emperor became milder, but did not completely give up his wrath; for although he ceased to put ecclesiastics to death, he continued to send them into exile, until this fury of his also was repressed by the following event.