Caesar's Rhine bridges

Caesar's bridges across the Rhine, the first two bridges on record to cross the Rhine River, were built by Julius Caesar and his legionaries during the Gallic War in 55 BC and 53 BC. Strategically successful, they are also considered masterpieces of military engineering.
During Caesar's conquest of Gaul it became necessary to secure the eastern border of the new provinces against marauding Germanic tribes. The tribes felt safe on the eastern side of the Rhine river, trusting the river as a natural border which offered cover from retaliatory attack after their opportunistic raids into the province. Caesar decided to confront them. He also wanted to show support for the Ubians, an allied German tribe across the Rhine. While he could have crossed the river by boats which the Ubians had offered to provide, he decided to build a bridge, thus demonstrating Rome's ability to bring the fight at any time to the Germanic tribes and additionally, as he indicated in his Commentary on the Gallic War, this approach conformed more to his own dignity and style, than to anything else.

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