<P> Muslim engineers adopted watermill technology from former provinces of the Byzantine Empire, having been applied for centuries in those provinces prior to the Muslim conquests, including modern - day Syria, Jordan, Israel, Algeria, Tunisia, Morocco, and Spain (see List of ancient watermills). </P> <P> The industrial uses of watermills in the Islamic world date back to the 7th century, while horizontal - wheeled and vertical - wheeled watermills were both in widespread use by the 9th century . A variety of industrial watermills were used in the Islamic world, including gristmills, hullers, sawmills, shipmills, stamp mills, steel mills, sugar mills, and tide mills . By the 11th century, every province throughout the Islamic world had these industrial watermills in operation, from al - Andalus and North Africa to the Middle East and Central Asia . Muslim and Middle Eastern Christian engineers also used crankshafts and water turbines, gears in watermills and water - raising machines, and dams as a source of water, used to provide additional power to watermills and water - raising machines . Fulling mills, and steel mills may have spread from Al - Andalus to Christian Spain in the 12th century . Industrial watermills were also employed in large factory complexes built in al - Andalus between the 11th and 13th centuries . </P> <P> The engineers of the Islamic world used several solutions to achieve the maximum output from a watermill . One solution was to mount them to piers of bridges to take advantage of the increased flow . Another solution was the shipmill, a type of watermill powered by water wheels mounted on the sides of ships moored in midstream . This technique was employed along the Tigris and Euphrates rivers in 10th - century Iraq, where large shipmills made of teak and iron could produce 10 tons of flour from corn every day for the granary in Baghdad . </P> <P> At the time of the compilation of the Domesday Book (1086), there were 5,624 watermills in England alone, only 2% of which have not been located by modern archeological surveys . Later research estimates a less conservative number of 6,082, and it has been pointed out that this should be considered a minimum as the northern reaches of England were never properly recorded . In 1300, this number had risen to between 10,000 and 15,000 . By the early 7th century, watermills were well established in Ireland, and began to spread from the former territory of the empire into the non-romanized parts of Germany a century later . Ship mills and tide mill were introduced in the 6th century . </P>

Difference between water mill and flour mill in points