The oldest cookie factory in the world may have been discovered in the south of France.
Scientists now believe that a huge Roman factory in Barbegal was used to produce sandwiches en masse to feed second-century sailors during long voyages at sea.
The huge water mill featured a large complex of 16 wooden wheels fed by 38 miles (60 km) of winding aqueducts.
As the water cascaded over the wheels, it turned a gear system that crushed grains into flour, which was then sent to nearby Roman ports.
Previously, researchers thought that large-scale watermills, such as Barbegal, were only used on an industrial scale several centuries later during medieval times.
Scroll down to watch the video
The Barbegal factory was a large complex of 16 water wheels stacked almost vertically in the south of France. Water entered from an aqueduct at the top of the site, flowing through each wheel, which was connected to a system of gears that ground the grain into flour (artist's impression)
WHAT ARE SHIP BOATS?
Ship biscuits were once a basic part of a sailor's diet on long trips.
It is simple biscuit or cookie, made of flour, water and sometimes salt.
Before the invention of canned products, few foods lasted more than a week before rotting or becoming obsolete.
The biscuits for ships can last for months and contain many calories for their size, which makes them ideal for long trips.
Also known as hardtacks, they were eaten by European sailors from the 12th century until the beginning of the 20th century.
It is believed that the Roman mill, discovered for the first time in 1937, is one of the oldest industrial complexes in the world and produces enough flour to feed 12,500 people each year.
Until now, researchers had assumed that the site was only used to supply flour to the nearby Roman city of Arelate.
However, a new analysis of the old limestone deposits found in the complex revealed that its wooden wheels stopped turning at the end of summer and autumn.
This suggests that the factory did not supply Arelate, since the city would have needed flour throughout the year and, in turn, probably has been used to supply the crews.
Scientists at the Johannes Gutenberg University in Mainz, Germany, analyzed the limestone found on the site shortly after its discovery.
The deposits had accumulated on the wheels while they were shaking in the water, and they are all that remains of the old wooden mechanism, which rotted centuries ago.
The chemical analyzes of the lime show that it was not deposited throughout the year, and suggest that the factory stopped producing in late summer and autumn.
Flour does not store as well as grain.
As a result, if the factory were used only to supply four to nearby Arelate, as previously suspected, it would have to be running continuously throughout the year.
It was thought that the Barbegal mill, which was fed by a vast aqueduct system (bottom left image), produced flour for the nearby Roman city of Arelate (top left). New research suggests that the flour went to nearby ports, and that the hydraulic wheels of the site were placed inside the buildings (bottom right), instead of outside (top right) as previously thought
The image is part of the aqueduct system used to feed the huge Roman Barbegal flour mill. The factory produced flour that was then used to make cookies for sailors
"For a major city, a supply is needed throughout the year," lead author of the study, Professor Cees Passchier, told New Scientist.
Instead, the mill could have made flour for shipping trips, which were seasonal: Roman ships avoided the Mediterranean during the winter due to storms.
The researchers suggest that this flour was transported to the nearby ports of Arles and Fossae Marianae, where it was used to make "shipping biscuits".
Also known as hardtacks, these simple cookies were made with flour, water and, sometimes, salt.
This image shows part of the stairs that flanked the wheels of the mill. The water mill had a large complex of 16 wooden wheels fed by 38 miles (60 km) of winding aqueducts
A long series of aqueducts (in the image) provided water to the mill. As the water cascaded down the wheels, it turned a gear system that crushed grains into flour, which was then sent to nearby Roman ports.
WHAT IS THE BARBERA FACTORY?
The Barbegal factory is the largest water-powered factory ever found in the world.
The Roman complex in the south of France has 16 hydraulic wheels stacked vertically and was built around the 4th century AD.
Scientists have previously suggested that the site, discovered in 1937, was used to supply flour to the nearby Roman city of Arelate.
The Barbegal factory in southern France is the largest and oldest water factory ever found in the world.
An aqueduct system about 38 miles (62 km) long feeds the city, stopping at the factory on the road.
It is thought that approximately half of the water provided by the aqueducts was used to power the installation.
New research suggests that the complex, located about 12 miles (19 km) from the French city of Barbegal, was used to produce cookies for Roman soldiers.
These simple snacks were incredibly popular among sailors before the invention of canned goods, as the cookies lasted for weeks without rotting or aging.
The researchers said that the crystal structure of limestone deposits reveals that they formed in the dark by fast-flowing water.
This suggests that the waterwheels were actually kept inside the small huts that lined the hill, rather than outside, as previous research suggests.
Watermills were used by ancient civilizations from Egypt to China to feed machinery such as mills and to raise water.
This image shows part of the Barbegal aqueduct. Chemical analyzes of lime found at the factory show that they were not deposited throughout the year, and suggest that the factory stopped producing in late summer and fall.
Barbegal is unique in that the site features 16 hydraulic wheels arranged in a pair of adjacent rows on a steep slope.
A 38-mile aqueduct system fed Arelate and the mill, which consumed half of the 45 million liters of water that passed through the canal per day.
It is believed that more of these vertical Roman watermills were built around Europe, but few have been found, since they were mostly made with wood, which decays rapidly.
In the photo, a shipping cracker manufactured by the British Navy at the beginning of the 20th century. It is on display at the Maritime Museum of Merseyside. The cookies were popular among sailors before the invention of canned products, as they lasted for weeks without rotting or aging