Thread: Roman Frontiers

A stunning network of walls, rivers, desert forts, and mountain watchtowers marks Rome’s limits. At its peak in the second century A.D., the empire sent soldiers to patrol a front that stretched from the Irish Sea to the Black Sea as well as across North Africa.

Why did the Romans build the walls? To protect a regime besieged by barbarians, or simply to establish the physical edge of the empire?

Faced with more territory than Rome could afford to control and under pressure from politicians and generals to follow in the footsteps of his adoptive father, the newly minted emperor—better known as Hadrian—blinked. “The first decision he made was to abandon the new provinces and cut his losses,” says biographer Anthony Birley. “Hadrian was wise to realize his predecessor had bitten off more than he could chew.”
The new emperor’s policies ran up against an army accustomed to attacking and fighting on open ground. Worse, they cut at the core of Rome’s self-image. How could an empire destined to rule the world accept that some territory was out of reach?
Hadrian may simply have recognized that Rome’s insatiable appetite was yielding diminishing returns. The most valuable provinces, like Gaul or Hadrian’s native Spain, were full of cities and farms. But some fights just weren’t worth it. “Possessing the best part of the earth and sea,” the Greek author Appian observed, the Romans have “aimed to preserve their empire by the exercise of prudence, rather than to extend their sway indefinitely over poverty-stricken and profitless tribes of barbarians.”
The army’s respect for Hadrian helped. The former soldier adopted a military-style beard, even in official portraits, a first for a Roman emperor. He spent more than half of his 21-year reign in the provinces and visiting troops on three continents. Huge stretches of territory were evacuated, and the army dug in along new, reduced frontiers. Wherever Hadrian went, walls sprang up. “He was giving a message to expansion-minded members of the empire that there were going to be no more wars of conquest,” Birley says.
By the time the restless emperor died in 138, a network of forts and roads originally intended to supply legions on the march had become a frontier stretching thousands of miles. “An encamped army, like a rampart, encloses the civilized world in a ring, from the settled areas of Aethiopia to the Phasis, and from the Euphrates in the interior to the great outermost island toward the west,” Greek orator Aelius Aristides noted proudly, not long after Hadrian’s death.
That “outermost island” was where Hadrian built the monument that bears his name, a rampart of stone and turf that cut Britain in half. Today Hadrian’s Wall is one of the best preserved, well-documented sections of Rome’s frontier. Remnants of the 73-mile barrier run through salt marshes, across green sheep pastures, and for one bleak stretch not far from downtown Newcastle, alongside a four-lane highway. Miles of it are preserved aboveground, lining crags that rise high above the rain-swept countryside.
More than a century of study has given archaeologists an unparalleled understanding of Hadrian’s Wall. The wall, perhaps designed by Hadrian himself on a visit to Britain in 122, was the ultimate expression of his attempt to define the empire’s limits.

For decades arguments focused on tactical details: Did soldiers stand along the wall to rain spears and arrows down on invaders or sally forth to engage the enemy in the field? The trenches of WWI—and the deadly back-and-forth battling of WWII—did little to change the prevailing view of the ancient frontier as a fixed barrier separating Rome from hordes of hostile barbarians.
Archaeologists studying the frontiers in the 1970s and ’80s later found that the Iron Curtain dividing Europe had shadowed their view of the distant past. “We had in Germany this massive border, which seemed impenetrable,” says C. Sebastian Sommer, chief archaeologist at the Bavarian State Preservation Office. “The idea was here and there, friend and foe.”
Today a new generation of archaeologists is taking another look. The dramatic, unbroken line of Hadrian’s Wall may be a red herring, a 73-mile exception that proves an entirely different rule. In Europe the Romans took advantage of the natural barriers created by the Rhine and Danube Rivers, patrolling their waters with a strong river navy. In North Africa and the eastern provinces of Syria, Judaea, and Arabia, the desert itself created a natural frontier.
Military bases were often ad hoc installations set up to watch rivers and other key supply routes. The Latin word for frontier, limes (LEE-mess), originally meant a patrolled road or path. We still use the term: Our “limits” comes from limites, the plural of limes.
Outposts on rivers like the Rhine and Danube or in the deserts on Rome’s eastern and southern flanks often resemble police or border patrol stations. They would have been useless against an invading army but highly effective for soldiers nabbing smugglers, chasing small groups of bandits, or perhaps collecting customs fees. The thinly manned walls in England and Germany were similar. “The lines were there for practical purposes,” says Benjamin Isaac, a historian at Tel Aviv University. “They were the equivalent of modern barbed wire—to keep individuals or small groups out.”
Isaac argues that the frontiers resembled certain modern installations more than thick-walled medieval fortresses: “Look at what Israel’s building to wall off the West Bank. It’s not meant to keep out the Iranian army, it’s made to stop people from exploding themselves on buses in Tel Aviv.” Warding off terrorists may not have motivated the Romans, but there were plenty of other factors— as there are today. “What the United States is planning between itself and Mexico is substantial,” says Isaac, “and that’s just to keep out people who want to sweep the streets in New York.”
More archaeologists are endorsing that view. “Isaac’s analysis has come to dominate the field,” says David Breeze, author of the recent Frontiers of Imperial Rome. “Built frontiers aren’t necessarily about stopping armies but about controlling the movement of people.” The Roman frontier, in other words, is better seen not as an impervious barrier sealing Fortress Rome off from the world but as one tool the Romans used to extend influence deep into barbaricum, their term for everything outside the empire, through trade and occasional raids.

Hadrian’s legacy was doomed. “The tragic point of their strategy is that the Romans concentrated military force at the frontier,” Meyer says. “When the Germans attacked the frontier and got in behind the Roman troops, the whole Roman territory was open.” Think of the empire as a cell, and barbarian armies as viruses: Once the empire’s thin outer membrane was breached, invaders had free rein to pillage the interior.

excerpts from Roman Frontiers - Pictures, More From National Geographic Magazine
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