In turn oxen and horses were soon being replaced by inanimate power. The watermill, known to the Romans but comparatively little used, became so common in the Dark Ages that by the time of the Domesday Book (1086), there was one for every fifty people in southern England. Two hundred years later, the number of watermills had doubled again. By 1300 there were sixty-eight watermills on a single mile of the Seine in Paris, and others floating on barges.
