Neolithic Motza plaster-making technique predates Roman Empire by 8,000 years

The Roman Empire reshaped human life for centuries during its dominance, and the imprint it left has carried on influencing civilisation ever since.

Yet even the ancient Romans built on foundations laid by others.

That debt is owed not only to earlier societies such as Egypt and Greece, but also to many prehistoric communities whose breakthroughs have largely faded from view - or have, in some instances, been mistakenly credited to later peoples.

A new study now reports that an advanced plaster-making method long associated with the Romans was already in use among Neolithic people around 8,000 years earlier.

So how could that be?

Roman building materials and dolomitic lime

Ancient Rome is celebrated for engineering achievements visible in enduring landmarks such as the aqueducts and the Pantheon. Beyond design and construction expertise, Roman builders are thought to have gained an advantage from long-lasting concrete and other high-grade materials.

Among these materials was a quick-setting, dolomite-based plaster used in some Roman structures. This paste is tougher and more resistant to water than the more common calcitic plasters widely produced in antiquity.

"However, using dolomitic lime is challenging and requires a high level of expertise at all steps of preparation, which may explain why it is not commonly found in archaeological sites," the researchers write.

Dolomite can refer to a mineral composed of calcium magnesium carbonate, or to a rock made up largely of that mineral. Like calcitic limestone, it can be used to obtain the inorganic substance lime, which then plays a role in producing certain building materials.

The study authors point out that the earliest written record of dolomitic lime appears to come from the Roman architect and engineer Vitruvius in the first century BCE.

Although Vitruvius did not explicitly name dolomite, he seemed to outline it while discussing how lime is made.

Plaster was already widely used long before Vitruvius, but there has been little sign that anyone employed dolomitic lime prior to his account roughly 2,000 years ago.

Archaeological finds indicate that, in prehistory, plaster was typically made using calcite and gypsum.

The Motza Neolithic settlement in the Judean Hills

According to the new research, though, people at a Neolithic settlement in the Judean Hills were apparently producing dolomite-based plaster about 10,000 years ago, leaving behind faint evidence that only now has been recognised.

Now within Israel and Palestine, this area was already a centre of human activity at the time, with settlements thriving millennia before the start of the Iron Age or the Roman Empire.

One such settlement later became the archaeological site of Motza, situated about 5 kilometres west of Jerusalem. Ahead of road-building in the area, researchers carried out a series of excavations there between 2015 and 2021.

Working through layers representing multiple periods of occupation, the team concentrated on a substantial Neolithic settlement dated to roughly 9,000 years ago. From this phase they uncovered more than 100 plaster floors, and they report that many were "particularly well-preserved and coated with red pigment".

In addition, they identified separate kilns in which inhabitants had burned either limestone or dolomite to produce plaster - a level of technical capability not often associated with Neolithic communities.

The researchers explain that calcitic and dolomitic lime demand different conditions during plaster manufacture. Even so, these prehistoric builders seemingly grasped the distinction well enough to construct dedicated kilns for each raw material.

A technique 8,000 years older than Rome

While turning dolomite into plaster was a notable accomplishment for people of that era, the approach used at Motza is, the researchers argue, striking even from a modern perspective.

"They may have successfully made dolomitic plaster where dolomite is fully recrystallized along with the calcite, something that to our knowledge has not been observed anywhere else and was thought to be physically impossible," they write.

Beyond taking advantage of plentiful local dolomite, this process would probably have produced a higher-quality plaster for building work - offering greater strength and improved resistance to water compared with traditional options.

Because dolomite-based plaster is difficult to make, and because earlier examples were not previously known, its invention has long been attributed to Ancient Rome.

The researchers note that the technique could, in principle, have persisted for 8,000 years after Motza before reappearing in Rome. However, the absence of archaeological evidence from the intervening period instead suggests the Romans arrived at the method independently.

"The results suggest a technology lost to history," the researchers write.

The study was published in the Journal of Archaeological Science.