Nicene and Post-Nicene Fathers, Ser. II, Vol. III:
The Ecclesiastical History, Dialogues, and Letters of Theodoret.: Of the letter written by Valens to the great Valentinianus about the war, and how he replied.

Chapter XXVIII.—Of the letter written by Valens to the great Valentinianus about the war, and how he replied.

The Lord roused the Goths to war, and drew on to the Bosphorus him who knew only how to fight against the pious. Then for the first time the vain man became aware of his own weakness, and sent to his brother to ask for troops. But Valentinian replied that it were impious to help one fighting against God, and right rather to check his rashness. By this the unhappy man was filled with yet greater infatuation, yet he did not withdraw from his rash undertaking, p. 130 and persisted in ranging himself against the truth. 801

Footnotes

On this Valesius remarks that Valentinian was already dead (†375) when the Goths crossed the Danube and ravaged Thrace (376). Theodoretus should have written “Gratianus” for “Valentinianus,” and “nephew” for “brother.”