Caesar's Rhine bridges

The tribes felt safe on the eastern side of the Rhine, trusting the river as a natural border which protected them from retaliation after their opportunistic raids into the province.

While he could have crossed the river by boats which the Ubians had offered to provide, Caesar decided to build a bridge to demonstrate Rome's ability to bring the fight at any time to the Germanic tribes.

Double timber pilings were rammed into the river bottom by raising a large stone with a winch and releasing it, driving the posts into the riverbed.

The most upstream and downstream pilings were slanted and secured by a beam, and multiple segments of these then linked up to form the basis of the bridge.

He crossed with his troops over to the eastern side and burned some villages but found that the Sugambri and Suebi tribes had moved eastward.

With Roman colonization of the Rhine valley more permanent bridges were built later at Castra Vetera (Xanten), Colonia Claudia Ara Agrippinensium (Cologne), Confluentes (Koblenz), and Moguntiacum (Mainz).