As a result of technological advances and shortages of enslaved workers, water power became used more widely in the Roman Empire around the late third century; the earliest known depiction of a water-powered stone sawmill was produced around this time in Hierapolis. Later, in 371, the poet Ausonius wrote an ode to the Moselle River: “He turns his millstones in furious revolutions and drives the shrieking saws through smooth blocks of marble.”