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The Barbegal watermill complex, a unique cluster of 16 waterwheels in southern France, was the first known attempt in Europe to set up an industrial-scale complex of machines during the culmination of Roman Civilization in the second century CE. Little is known about the state of technological advance in this period, especially in hydraulics and the contemporary diffusion of knowledge. Since the upper part of the Barbegal mill complex has been destroyed and no traces of the wooden machinery survived, the mode of operation of these mills has long remained elusive.