A stunning map created by archaeologists gives you a new reason to think about the Roman Empire

How often do you think about the Roman Empire?

For a team of international researchers who went all in and mapped the ancient Roman road system, the answer — truly — is every day. And now, anyone can dive into the newly created visualization tool, which includes 100,000 kilometers (about 62,000 miles) of newly identified routes, and virtually explore how ancient Romans traveled.

At its peak, the Roman Empire stretched from modern-day Britain to Egypt and Syria, and its impressive network of roads contributed to its successful expansion. The astonishing map, which lays out the Roman road system around AD 150, spans over 300,000 kilometers (about 186,000 miles) — enough to circle Earth more than seven times, Dr. Pau de Soto, coauthor of the study describing the tool, said in an email. He is a professor in the department of ancient and medieval history at the Autonomous University of Barcelona in Spain.

The expansive map can help support future research that explores the influence Roman roads had on connectivity and migration as well as disease transmission, and the long-term effects these events had on the empire, experts say.

Travel as an ancient Roman

Those living during the Roman Empire had many different modes of transportation: Egyptians mainly relied on camels, while people in other areas of the empire rode horseback or traveled via carts and pack mules. Sometimes they used chariots or simply walked, said Dr. Catherine Fletcher, a professor of history at Manchester Metropolitan University in the UK and author of the book “The Roads to Rome: A History of Imperial Expansion.”

In some areas, the roads were paved, while away from civilization they were topped with a layer of small stones. It’s still possible to walk down some of these roads, such as the Appian Way leading into Rome, she added.

“This dataset brings together a huge range of research to give a bigger and more comprehensive picture of the Roman road network than we’ve had before. It also shows just how much we still don’t know about the roads, despite their fame,” said Fletcher, who was not involved with the new study.

“The visualisations will be a great help for writers or filmmakers looking to imagine how trips across the Roman Empire might have looked, and it’ll be fun for anyone who wants to explore a Roman road in their own locality or when they’re on vacation,” she added in an email.

The map is an evolving project, de Soto said, and additions are still being made to it. The authors hope to add maritime and river connections soon and to explore the chronological evolutions of the roads, he added.

“The Roman (Empire) was the earliest example of a continental scale integrated political and economic unit,” said study coauthor Tom Brughmans, an associate professor of classical archaeology at Aarhus University in Denmark. “This period fundamentally restructured transport infrastructure in the region, in a scale unseen until the industrial revolution in the 19th century, and we now have the dataset that allows us to study how terrestrial mobility changed over (2,000) years.”

Mapping ancient Roman roads

Laying the groundwork for the map, named Itiner-e, required the researchers to cross-reference many historical records as well as satellite imagery, historical aerial photographs and other data. The map offers the ability to calculate journey times between different locations and helps to highlight gaps that remain missing in scientists’ knowledge of the ancient roads.

Putting together 200 years of research on the Roman roads to create the visualization was like “a giant game of connecting the dots,” Brughmans said.

“We know hundreds of thousands of ancient places like cities and villas where the Romans lived and worked,” Brughmans added in an email. “But roads are long linear features cutting through a landscape that are hard to excavate in their entirety.”

The authors found traces of these ancient roads by comparing historical evidence — such as items found during excavation or in historical travel records — with satellite imagery and topographic maps that show a time before dense urbanization. They even uncovered roads that are currently hidden under dam lakes by using historical satellite images that reveal what the area once looked like, Brughmans said.

However, while the map adds to scientists’ understanding of the ancient travel network, the authors noted that only 2.7% of roads are certain to have an exact location. About 90% of the map is less precisely known, and the remaining 7% are only hypothesized roads.

“This was a huge surprise and a sobering realisation: roads are one of the most enigmatic topics in Roman archaeology and history, they were all over the place, we have proverbs like ‘all roads lead to Rome,’” Brughmans said.

“How can it be that we only know the location of 3% with certainty?” he added.

That question serves as a call to action for researchers to map other less-known parts of the ancient empire, such as “areas where we know the road data is not very representative because there are many ancient places with no roads leading to them,” he said.

For now, the map provides visual data for understanding how the civilization moved and evolved, helping to identify routes for the dispersion of goods, the circulation of diseases or the spread of ideas, de Soto said.

The researchers reported the findings Thursday in the journal Scientific Data.

Taylor Nicioli is a freelance journalist based in New York.

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