Hierapolis Sawmill was a Roman water-powered stone sawmill in Hierapolis, Asia Minor (modern-day Turkey). Dating to the second half of the 3rd century, [2] it is considered the earliest known machine for combining timber with a crank to form a connecting rod with a crank-shift mechanism.
The watermill is evidenced by the raised relief on the sarcophagus of a local miller, Marcus Aurelius Ammianos. The open pediment of a water wheel fed a mill race is shown to be closed with a gear set, two frame saws and cranks cutting rectangular blocks through connecting rods, by mechanical necessity (see diagram). The accompanying inscription is in Greek and attributes the mechanism to the "wheel skills" of Ammianos.
Other Roman crank and connecting rod mechanisms, without gearing, have been archaeologically confirmed for water-powered stone sawmills in Gerasa, Jordan, and Ephesus, Turkey, in the 6th century AD. A fourth sawmill probably existed in Augusta Raurica, Switzerland, where a metal crankshaft was excavated from the 2nd century AD.
Literary references to the water-powered marble saws at Trier, now Germany, can be found in Ausonius' poem Mosella, written in the late 4th century AD. About the same time, they also seem to be illustrated by the Christian saint Gregory of Nyssa, showing the diversified use of water power in many parts of Anatolia from the Roman Empire.
Three finds push back the invention date of the crank and connecting rod mechanism by a millennium; For the first time, all the essential components of the much later steam engine were combined by a single technological culture.
