Mills were the equivalent of medieval factories, places where machinery provided a lot of the hard work that made it possible for people to do more than they could have through their own physical labor. Although there were some precursors in the ancient world, mills, essentially in the form they kept through the nineteenth century, are medieval inventions. (Below is a picture of a nineteenth-century water mill.) Big electricity-generating windmills and water mills ("hydro power") show that mills are still very important, even though the technology has changed.
The Romans had had water mills, but they treated them as toys; none of them were more than miniature little mechanical contraptions that looked cute when water ran through them. Windmills appear to have developed originally in central Asia and spread very rapidly across Europe in the twelfth century. (Contrary to what you may have heard, windmills do not cause cancer.)
Windmills predominated where there was strong and steady wind. Water mills could be set up on any rapidly running stream, or, as in the picture above, a race could take water from a stream and funnel it to a mill, with a big drop (fall) to power the wheel. Medieval streams were thick with mills, and there were always quarrels about people damming streams (to create the big drop of water) and depriving people downstream of water. Along the coast there were tide mills.
If you have ever visited a historic mill, you have probably been impressed by all the gears. The wind or water drives a shaft around and around, and gears and ropes take that power off for useful purposes. Because, I have discussed earlier, bread was the single biggest item in the medieval diet, grinding grain into flour was the most important function of a mill. In ancient Rome, it would take a slave all day with a hand mill to grind enough flour for the household for that day. With a mill, you could grind a 50 pound sack of grain into a 50 pound sack of flour in half an hour. Big millstones ground against each other to break the hard grains of wheat into flour.
It's actually possible to tell if a community had adopted mill-ground flour, because a tiny amount of stone dust gets into the flour and wears down people's teeth, which is evident in skeletal remains.
Mills had many other uses. They could power hammers, used both in forging and in "fulling," the beating of woolen cloth to make it thick and tight (like what we call boiled wool). They could also be used for sawing lumber, again making the work much easier for humans; we still speak of sawmills. With all the ropes and gears mills could be dangerous places, but the miller was a highly revered member of the community. Some lords and monasteries insisted that the local inhabitants grind their grain only in their mills (for a fee of course), to make back the substantial expense of building one.
As Americans moved west in the nineteenth century, one of the first things to be established in a new community was a mill.
© C. Dale Brittain 2020
Read more about medieval food and technology in my ebook, Positively Medieval: Life and Society in the Middle Ages, available on Amazon and other ebook platforms. Also available in paperback!