The Roman History · Amm. 30.7.6

And Valentinian was deservedly dreaded by them because he took care to keep up the numbers of his army by strong reinforcements, and because also he fortified both banks of the Rhine with lofty fortresses and castles, to prevent the enemy from ever passing over into our territory without being perceived.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
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