Zosimus, New History 6.05
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 Zosimus' New 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.
[6.5.1] After these achievements in Spain, Constans returned to his father, carrying with him Verenianus and Didymius, and leaving there his general Gerontius with the Gallic troops to guard the pass from Celtica into Spain, although the Spanish soldiers desired that charge to be confided to them, as had formerly been the case, and that the safety of their country might not be committed to the care of strangers.
[6.5.2] Verenianus and Didymius, being brought to Constantine, were immediately put to death. Constans was afterwards a second time sent into Spain, and took with him Justus as his general. Gerontius being dissatisfied at this, and having conciliated the favor of the soldiers in that quarter, incited the barbarians who were in Gallia Celtica to revolt against Constantine. Constantine being unable to withstand these, the greater part of his army being in Spain, the barbarians beyond the Rhine made such unbounded incursions over every province, as to reduce not only the Britons, but some of the Celtic nations also to the necessity of revolting from the empire, and living no longer under the Roman laws but as they themselves pleased.
[6.5.3] The Britons therefore took up arms, and incurred many dangerous enterprises for their own protection, until they had freed their cities from the barbarians who besieged them. In a similiar manner, the whole of Armorica, with other provinces of Gaul, delivered themselves by the same means; expelling the Roman magistrates or officers, and erecting a government, such as they pleased, of their own.