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In 55 BC Julius Caesar marched through Europe, crushing the rebellious tribes in the North. In mid-summer he
arrived at the mighty Rhine. He was determined to get his legions across to teach the tribes on the other side
a lesson, but considered it beneath the dignity of the Roman army to cross the river by boat. Consequently, he
ordered his men to build a wooden bridge over a river which was at least 400 metres wide, up to 8 metres
deep and flowing at 2 metres a second. In his account of 'The Gallic Wars' he claims that from the felling of the first tree to the completed bridge, this massive structure was built in only ten days. Caesar's Bridge attempts to discover if Caesar was boasting.


Caesar left a surprisingly detailed account of how the bridge was built. Based on a series of trestles spaced
across the river, it was unusual in a number of ways. For example, the pairs of timber piles that formed the
trestles were driven in to the river bed at a slanting angle to provide more stability.This is much harder to
achieve than the more usual vertical piling. Caesar tells us that 'the stability of the structure was so great and its character such that, the greater the force and thrust of the water, the tighter were the balks held in lock.'
But how did Caesar's engineers pile 8 metre long oak timbers into the pebbly bed of the Rhine at an angle? The first challenge is to design and build a Roman pile-driver, with no evidence to go on.