The initial invention of the watermill appears to have occurred in the Hellenized eastern Mediterranean in the wake of the conquests of Alexander the Great and the rise of Hellenistic science and technology. In the subsequent Roman era, the use of water-power was diversified and different types of watermills were introduced. These include all three variants of the vertical water wheel as well as the horizontal water wheel. Apart from its main use in grinding flour, water-power was also applied to pounding grain, crushing ore, sawing stones and possibly fulling and bellows for iron furnaces.
