Before the mill, the quern
For thousands of years, flour was made by grinding grain between stones by hand. The work was slow and fell mostly to women in many societies. A device that could turn a heavy stone using flowing water meant that one machine could do the work of many hands, and that is the reason water mills drew so much interest.
The waterwheel has no known single inventor and no secure date of origin. The earliest evidence is in written sources and archaeology from the Mediterranean and the Near East in the last centuries BCE. This article concentrates on that early period. The later spread across Europe is covered in the piece on medieval mills.
The earliest evidence
References to water-powered grain mills appear in Greek and Roman writing from about the first century BCE. The geographer Strabo describes a water mill in the palace of the king of Pontus, in northern Anatolia. A short poem attributed to Antipater of Thessalonica praises the water-driven mill for freeing women from the work of grinding. The Roman architect Vitruvius gives a description of a water-driven mill and its gearing in his book on architecture, written in the late first century BCE.
The dating of these sources is not always exact, and some historians think the technique could be older than the written records show. It is also unclear in which region it first arose. The mill design may have developed in the eastern Mediterranean or the Near East, and spread from there. Scholars continue to debate this.
Two basic designs
Two types of wheel are associated with early mills.
- The horizontal wheel lies flat in the water, with the millstone mounted directly on a vertical shaft above it. It is simple, needs no gears and works best in a fast, steep stream. Mills of this type are thought to be older and remained common in mountainous regions.
- The vertical wheel stands upright, like a cartwheel, and drives the stones through a right-angle gear. It needs more complicated woodwork but can use gentler rivers and can be adapted to drive other machinery. Vitruvius describes this type.
Roman engineering at scale
The Romans built water mills at a larger scale than earlier evidence suggests. The best-known site is Barbegal, near Arles in southern France, where the remains of a mill complex on a hillside were fed by an aqueduct. It is often described as having sixteen wheels arranged in two lines down a slope, with water passing from one wheel to the next, and is dated to around the second century CE. Estimates of how much flour it could produce vary widely, and scholars disagree about how continuously it ran and who it served. It should be treated as an impressive but uncertain example.
Water mills were also placed on rivers in Rome itself. Reports of mills on the Janiculum hill and on boats moored in the Tiber, from late antiquity, show that the technology was adopted for city supply.
Beyond grinding
Early water power was not limited to flour.
- Sawing. A relief from Hierapolis in what is now Turkey, usually dated to the third century CE, shows a water-powered saw cutting stone. It appears to use a crank and connecting rod to turn rotary motion into back-and-forth motion, one of the earliest known examples. A poem by the Roman writer Ausonius from the fourth century CE mentions a mill sawing marble on a river in Germany.
- Hammers and crushing. Water-driven trip hammers and stamping mills were used in mining and in processing ores, and, as the Middle Ages went on, in forging metal. The detail of ancient use is less certain, since evidence is sparse.
- Lifting water. The same principle, buckets on a wheel turned by a current, was used for raising water to irrigation channels. Wheels of this type, called noria, were used in the eastern Mediterranean and the Near East and may be related to the mill, although how the two developed together is not settled.
Why it did not transform the ancient economy
If water mills were so useful, why did they not spread faster? Historians have offered several reasons, none of them certain. Water power requires a reliable stream and some capital to build. Cheap labor, including enslaved labor, may have reduced the incentive in some areas. Mills were also tied to the places where water was available, which was not always where grain needed to be ground. The mill’s spread seems to have picked up in late antiquity and the early Middle Ages, but exactly why is still discussed.
Toward industry
The idea that running water can supply mechanical power was the main lesson of these early mills, and later builders applied it again and again. Cams, gears, cranks and shafts developed or refined around mills became ordinary parts of machinery. In the eighteenth century the same basic source of power drove the early textile mills of Britain, as in the story of the water frame, before steam engines made factories independent of rivers.
The ancient mill therefore matters less for how many were built than for what it demonstrated: a rotating wheel could be connected to different tools. That principle, once understood, did not go away.