Julius Caesar is one of the greatest leaders in world history. This is evidenced by his victories in Spain (61 BCE), the conquest of Gaul (58-50 BCE), the invasion of Britain (54-53 BCE) or, for example, military campaigns east of the Rhine (55 and 53 BCE). Especially, the expeditions against the Germanic tribes prove how bold and ambitious Caesar was, who for the purposes of the campaign decided on an extremely complicated move for those times – the construction of a bridge over one of the longest rivers in Europe.
The reason for Caesar’s decision to go on a campaign east of the Rhine was to “temper” the arrogant and warlike Germanic tribes that invaded Gaul and were a threat to Caesar’s plans and allies. For the Germans, the Rhine was a natural barrier that prevented any invasion of their settlements. Caesar wanted to destroy this belief and, at the same time, probably discover the wild world of the Germans.
The allied Ubii tribe pledged to help Caesar, offering their river ships to transport his legions to the eastern bank of the Rhine. Caesar, however, refused and decided to demonstrate the power of engineering and military thought of Rome. On the Rhine, near Koblenz (western Germany), a wooden bridge was built, which was entirely built by Caesar’s soldiers. This is how Caesar himself describes it:
He devised this plan of a bridge. He joined together at the distance of two feet, two piles, each a foot and a half thick, sharpened a little at the lower end, and proportioned in length, to the depth of the river. After he had, by means of engines, sunk these into the river, and fixed them at the bottom, and then driven them in with rammers, not quite perpendicularly, dike a stake, but bending forward and sloping, so as to incline in the direction of the current of the river; he also placed two [other piles] opposite to these, at the distance of forty feet lower down, fastened together in the same manner, but directed against the force and current of the river. Both these, moreover, were kept firmly apart by beams two feet thick (the space which the binding of the piles occupied), laid in at their extremities between two braces on each side, and in consequence of these being in different directions and fastened on sides the one opposite to the other, so great was the strength of the work, and such the arrangement of the materials, that in proportion as the greater body of water dashed against the bridge, so much the closer were its parts held fastened together. These beams were bound together by timber laid over them, in the direction of the length of the bridge, and were [then] covered over with laths and hurdles; and in addition to this, piles were driven into the water obliquely, at the lower side of the bridge, and these, serving as buttresses, and being connected with every portion of the work, sustained the force of the stream: and there were others also above the bridge, at a moderate distance; that if trunks of trees or vessels were floated down the river by the barbarians for the purpose of destroying the work, the violence of such things might be diminished by these defenses, and might not injure the bridge.
– Julius Caesar, Gallic War, IV.17
By building the bridge, Caesar proved that Roman weapons could reach anywhere, regardless of the conditions and difficulties. What’s more, having around 40,000 soldiers at his disposal, Caesar built the bridge in just 10 days, which is an extremely impressive achievement.
After the bridge was built, Caesar crossed the Rhine with the legions, and then went to the lands of the Sugambri tribe, where he also burned their many villages. The rest of the tribes either sent messengers to ask for peace or evacuated their people to forests and wastelands and gathered warriors.
As Caesar informs when:
[…] having already accomplished all these things on account of which he had resolved to lead his army over, namely, to strike fear into the Germans, take vengeance on the Sigambri, and free the Ubii from the invasion of the Suevi, having spent altogether eighteen days beyond the Rhine, and thinking he had advanced far enough to serve both honor and interest, he returned into Gaul, and cut down the bridge
– Julius Caesar, Gallic War, IV.19
It was not the only bridge built on the Rhine by Caesar. Two years later, in a similar region, another bridge was built in a few days through which the Roman army once again crossed. Just like in 55 BCE Caesar encountered no strong resistance and no major battle ensued. The Suebi – Rome’s main opponents – withdrew to the forests.
Caesar, after he discovered through the Ubian scouts that the Suevi had retired into their woods, apprehending a scarcity of corn, because, as we have observed above, all the Germans pay very little attention to agriculture, resolved not to proceed any further; but, that he might not altogether relieve the barbarians from the fear of his return, and that he might delay their succors, having led back his army, he breaks down, to the length of 200 feet, the further end of the bridge, which joined the banks of the Ubii, and at the extremity of the bridge raises towers of four stories, and stations a guard of twelve cohorts for the purpose of defending the bridge, and strengthens the place with considerable fortifications. Over that fort and guard he appointed C. Volcatius Tullus, a young man.
– Julius Caesar, Gallic War, VI.29