De Bello Gallico 6.29

6.29.1Caesar, postquam per Ubiōs explōrātōrēs comperit Suēbōs sēsē in silvās recēpisse, inopiam frūmentī veritus, quod, ut suprā dēmōnstrāvimus, minimē omnēs Germānī agrīcultūrae student, cōnstituit nōn prōgredī longius;

Caesar learned through Ubian scouts that the Suebi had withdrawn into the forests; fearing a shortage of grain, because, as we have shown above, the Germans pay very little attention to farming, he decided not to advance farther;

6.29.1sed, nē omnīnō metum reditūs suī barbarīs tolleret atque ut eōrum auxilia tardāret, reductō exercitū partem ultimam pontis, quae rīpās Ubiōrum contingēbat, in longitūdinem pedum ducentōrum rescindit atque in extrēmō ponte turrim tabulātōrum quattuor cōnstituit praesidiumque cohortium duodecim pontis tuendī causā pōnit magnīsque eum locum mūnītiōnibus firmat.

but so as not to remove entirely the barbarians' fear of his return, and to delay their reinforcements, after leading his army back he cut down the last part of the bridge, which touched the bank of the Ubii, for a length of two hundred feet; at the end of the bridge he built a tower four stories high, placed a guard of twelve cohorts to protect the bridge, and strengthened the place with large fortifications.

Note. tabulātōrum quattuor: genitive of description, 'of four stories'. This bridge is the second one Caesar built across the Rhine (chapter 9).

6.29.3Eī locō praesidiōque Gāium Volcātium Tullum adulēscentem praefēcit.

He put the young Gaius Volcatius Tullus in command of that place and its garrison.

6.29.4Ipse, cum mātūrēscere frūmenta inciperent, ad bellum Ambiorīgis profectus per Arduennam silvam, quae est tōtīus Galliae maxima atque ab rīpīs Rhēnī fīnibusque Trēverōrum ad Nerviōs pertinet mīlibusque amplius quīngentīs in longitūdinem patet, Lūcium Minucium Basilum cum omnī equitātū praemittit, sī quid celeritāte itineris atque opportūnitāte temporis prōficere possit;

He himself, when the grain was beginning to ripen, set out for the war against Ambiorix through the Ardennes forest, which is the largest in all Gaul and stretches from the banks of the Rhine and the borders of the Treveri to the Nervii over a length of more than five hundred miles; he sent Lucius Minucius Basilus ahead with all the cavalry, in case he could gain any advantage by the speed of his march and the favorable moment;

6.29.5monet, ut ignēs in castrīs fierī prohibeat, nē qua eius adventūs procul significātiō fīat: sēsē cōnfestim subsequī dīcit.

he warned him not to allow fires in the camp, so that there might be no sign of his approach from afar, and said that he would follow immediately.