Zosimus, New History 1.30

Zosimus (Greek Ζώσιμος): Early Byzantine, pagan author of a history of the Roman Empire, published in the first quarter of the sixth century CE.

The translation of ZosimusNew History offered here was printed in 1814 by W. Green and T. Chaplin in London, and was probably prepared by J. Davis of the Military Chronicle and Military Classics Office. The translator is anonymous. The text was found at Tertullian.org. The notes were added by Jona Lendering.

[1.30.1] Valerian, perceiving the empire in danger on every side, associated his son Gallienus with himself in the government and went himself into the east to oppose the Persians. He entrusted to his son the care of the forces in Europe, thus leaving him to resist the barbarians who poured in upon him in every direction.

[1.30.2] As the Germans were the most troublesome enemies, and harrassed the Gauls in the vicinity of the Rhine, Gallienus marched against them in person, leaving his officers to repel with the forces under their command any others that should enter Italy, Illyricum, and Greece. With these designs, he possessed himself of and defended the passages of the Rhine, at one time preventing their crossing, and at another engaging them as soon as they had crossed it. 

[1.30.3] But having only a small force to resist an immense number, he was at a loss how to act, and thought to secure himself by a league with one of the German princes. He thus not only prevented the other barbarians from so frequently passing the Rhine, but obstructed the access of auxiliaries.