Hierapolis sawmill

Dating to the second half of the 3rd century AD,[2] the sawmill is considered the earliest known machine to combine a crank with a connecting rod to form a crank-slider mechanism.

On the pediment a waterwheel fed by a mill race is shown powering via a gear train two frame saws cutting rectangular blocks by the way of connecting rods and, through mechanical necessity, cranks (see diagram).

[3] Further Roman crank and connecting rod mechanisms, without gear train, are archaeologically attested for the 6th century AD water-powered stone sawmills at Gerasa, Jordan,[4] and Ephesus, Turkey.

[6] Literary references to water-powered marble saws in Trier, Germany, can be found in Ausonius' late 4th century AD poem Mosella.

[7] The three finds push back the date of the invention of the crank and connecting rod mechanism by a full millennium;[8] for the first time, all essential components of the much later steam engine were assembled by one technological culture: With the crank and connecting rod system, all elements for constructing a steam engine (invented in 1712) — Hero's aeolipile (generating steam power), the cylinder and piston (in metal force pumps), non-return valves (in water pumps), gearing (in water mills and clocks) — were known in Roman times.