Along with the legions, the milestones marked the power of the . Placed every thousand suffering or Roman mile (1,478.5 meters), these cylindrical or parallelepiped markers marked the Roman roads, as kilometer points do today with highways. A large group of researchers has used the most modern technology to delve into historical and archaeological records to reconstruct the road map from 2,000 years ago. What they have discovered is that it was much larger, almost double, than previously believed. But they have also verified that hardly anything remains of its original layout. The results of their work, published in , have been gathered and opened to the public on the site , a digital atlas of the roads that began or died in Rome.
“When you pass through a path that has been very sunken by the passage of time and people, it is still said that ‘it was a Roman road’, but the Romans made them so that they would last,” says Pau de Soto, from the Archeology Research Group of the Universitat Autònoma de Barcelona (UAB) and first author of this impressive work. “Another belief to be disproven is that they made them paved, like the Appian Way. In reality, they made them with layers of increasingly finer gravel, with the tread layer formed by compacted fine gravel. It was the best for the passage of the horses, which at that time did not yet wear horseshoes,” adds the archaeologist. As with current roads, they were raised above the surrounding terrain and with a slight slope so that water could be evacuated. “The first modern roads were made following the Romans,” remembers this archaeologist.
Pau de Soto and around twenty researchers have used modern GIS (Geographic Information System) techniques to unearth the layout of the Roman roads. “GIS is the basis of modern archaeological research,” says the UAB researcher. They combined historical texts such as Antonine itinerary o to Tabula Peutingerianathe closest thing to a road map of antiquity, with studies on archaeological sites, or Roman history books. “But also with topographic maps from the 19th and 20th centuries, the photographs that Americans took of European soils in the postwar period or satellite images; GIS allows you to combine information from all these sources and capture it on the ground,” adds de Soto.
The result of the sum of so many sources is that, around the year 150 of this era, the Roman Empire—then at its time of greatest expansion, covering some four million square kilometers of territory—had 299,171 kilometers of roads. The figure represents adding more than one hundred thousand to the 188,555 km counted in previous works and is equivalent to circling the planet seven times. In Spain alone, the length of Roman roads exceeded 40,000 km, doubling the amount assumed until now. At that time there was no radial distribution centered in Madrid that characterizes modern roads, but some of the main roads started from cities such as Augusta Emerita (Mérida), capital of Roman Lusitania.
The authors of the new study estimate that a third linked major urban centers; and the remaining two-thirds would be secondary, connecting populations at a local or regional scale. However, they have verified that there is only 2.7% certainty of the mileage. “It is what is still preserved or that has been excavated in archaeological work,” details de Soto, who explains that, of the vast majority of Roman roads – almost 90% – there are only clues that they must have been there: “We call them fossilized axes, and they can be a Roman bridge, the remains of a road at the exit of the city or the discovery of a milestone.” Everything indicates that a road must have united all these elements. What a GIS does with them is imagine the most reasonable route taking into account the topography of the terrain, such as crossing a mountain or fording a river. Another 7% of the total of that road map It would only be hypothetical: if there are two nearby Roman cities with remains of a road at their exit, it would be expected that they would be linked by one.
“The roads—and the transportation network, as a whole—were absolutely crucial to the maintenance of the Roman Empire,” maintains historian at Aarhus University (Denmark) and co-author of the study, Adam Pažout. “The Romans devised an intricate transportation system made up of inns, way stations, and relay points for messengers and public officials traveling through Italy and the provinces,” he recalls. For Pažout, “the roads constituted a scaffolding that allowed Roman power to be projected, whether through the army or law and administration, and that kept the Empire together.”
According to the authors, their work will allow a better knowledge of the history of Rome. Millions of people moved along the roads, new ideas and beliefs spread; and through them the Roman legions or trade between the different parts of the three continents that formed the Roman territory also advanced. But these routes, whose enormous capillarity is now discovered, also facilitated plagues such as the Antonine plague of smallpox or measles or Justinian’s plague of bubonic plague, which weakened the Empire. They could also have been the entry routes for successive barbarian invasions.
What remains of the Roman roads, although physically not many kilometers, is part of the framework of Europe. Archaeologist de Soto remembers it: “The European urban fabric is a legacy of Rome. Most European cities already existed in Roman times and were already connected to each other.”
