Limits of Empire

Rome's Borders

Simon Forty, Jonathan Forty

• Publisher: Casemate
• Year: 2022
• ISBN:
  9781636240770
• Topic: Historia
• Subtopic: Historia antigua romana

The borders of the Roman Empire were frontiers that were often wild and dangerous. The expansion of the empire after the Punic Wars saw the Roman Republic become the dominant force in the Mediterranean as it first took Carthaginian territories in Gaul, Spain and north Africa and then moved into Greece with purpose, subjugating the area and creating two provinces, Achaea and Macedonia. The growth of the territories under Roman control continued through the rise of Julius Caesar – who conquered the rest of Gaul – and the establishment of the empire: each of the emperors could point to territories annexed and lands won.
By AD 117 and the accession of Hadrian, the empire had reached its peak. It held sway from Britain to Morocco, from Spain to the Black Sea. And its wealth was coveted by those outside its borders. Just as today those from poorer countries try to make their way into Europe or North America, so those outside the empire wanted to make their way into the Promised Land – for trade, for improvement of their lives or for plunder. Thus the Roman borders became a mix – just as our borders are today – of defensive bulwark against enemies, but also control areas where import and export taxes were levied, and entrance was controlled. Some of these borders were hard: the early equivalents of the Inner German Border or Trump’s Wall – Hadrian’s Wall and the line between the Rhine and Danube. Others, such as these two great rivers, were natural borders that the Romans policed with their navy.
This book examines these frontiers of the empire, looking at the way they were constructed and manned and how that changed over the years. It looks at the physical barriers – from the walls in Britain to the Fossatum Africae in the desert. It looks at the traders and the prices that were paid for the traffic of goods. It looks at the way that civil settlements – vici – grew up around the forts and fortlets and what life was like for soldiers, sailors and civilians.
As well as artefacts of the period, the book provides a guidebook to top Roman museums and a gazetteer of visitable sites

1 Border Expansion

Deir el-Munira fort in el-Kharga oasis, Egypt (see pp. 170–71) was built under Diocletian.

The Roman Republic started small around 500BC and had no real concern about frontiers as it fought first for survival and then to control the Italian peninsula. During this struggle it came up against large-scale barbarian attacks—by the Senones in 390BC and the Cimbri in 113–101BC. Its survival gave Romans a sense of destiny that was enhanced when they fought the Mediterranean superpower of the time, Carthage, and won. Victory in the first Punic war gave Rome its first province: Sicily, in 241BC. The second Punic war ended with Rome’s strength established having acquired Carthage’s possessions and comprehensively defeated its armies.

The second and first centuries BC saw Rome’s territories grow even further: Pompey and Caesar ensured that when Octavian Caesar became emperor, his empire stretched from the English Channel to Syria. They had, however, prodded a hornet’s nest: the Parthian Empire would be a continuous irritation in the east. The last years of the Republic were riven by internal strife, but a debilitating civil war didn’t stop the growth of the empire. By the death of Augustus in AD14, it had expanded far enough that the first serious thought was given to the empire’s borders and methods of protecting them.

When Augustus became emperor he had some sixty legions, including those of Mark Anthony, although not all at full strength. He gradually reduced this number to twenty-eight, creating a standing army for the first time consisting of some 150,000 Roman legionaries and about the same number of auxiliaries. The latter were recruited from foreign tribes and those as yet unqualified for citizenship within the empire. He then moved the legions away from the center to the periphery, and tasked them with the continued vigorous expansion and policing of Rome’s borders. Augustus was fortunate in having an experienced high-caliber team around him who had fought for his cause in the recent civil wars. This included his close and trusted childhood friend Marcus Agrippa, an outstanding general and administrator who shared Octavian’s vision and was responsible for making much of it become reality.

At first, Augustus continued Rome’s expansion. Egypt was annexed in AD30 and in the next five years his adopted sons Tiberius and Drusus conquered Noricum and Raetia (now Switzerland, Austria, and Bavaria) while Agrippa completed the conquest of northern Spain. In AD25 Celtic Galatia in what is now central Turkey was annexed, and in AD22 Augustus traveled east to Sicily, Greece, and the new Roman province of Asia (Anatolia) in a huge reorganization of administration and infrastructure. By AD20 he had reached a peace agreement with Parthia which included its acceptance of Armenia as a client kingdom within the Roman sphere of influence. In the north, Balkan and German campaigns aimed to extend Roman control up to a line from the Danube to the Elbe. However, Augustus was running out of family generals. Both Agrippa’s sons, adopted by Augustus, had died (in AD2 and 4). Of Augustus’s other adopted sons, Drusus died in Germany in AD6, leaving only his brother Tiberius. All of these men had shown great promise as fine generals in their various military exploits, but now they were gone.

The growth of the Roman Empire between 100BC. and AD 117. A superpower after defeating the Carthaginians, by the end of Trajan’s reign the empire had expanded to its greatest extent. It hadn’t had need for borders because it continued to expand. Much as “Manifest Destiny” propelled the United States to expand across the American continent, so the Romans thought of “an empire without limit.”

On top of the death of his youthful generals, there was a ghastly defeat for Varus’s three legions in the Teutoburger Wald in AD9, and then Agrippa died in AD12. Augustus was deeply affected by the former. This was probably the point when consolidation and even caution became the most realistic policy. He withdrew back to the Rhine and began to enhance it with defensive installations. Small forts, watchtowers, and signal stations linked by road were constructed to contain attacks or summon reinforcements, while larger ones covered critical access points. A riverine fleet was formed to patrol and police the river and intercept trouble when it came. As well as a line of defense, these beginnings of a linear barrier enabled the surveillance of tribal movements and also served as a more efficient customs barrier with which to regulate and tax trade.

Augustus continued with his review of his empire’s borders, his approach varying from region to region, adjusting for individual circumstances and contingencies. Sometimes a different, more flexible strategy was evolved, seeking to maintain peace through a combination of security, trade, and diplomacy. By allying with friendly local tribes and rewarding their loyalty with cash payments and the promise of mutual protection, he sought to create a buffer zone against those more hostile. He also continued building within the empire, equipping it with a superb network of roads for swift movement and to facilitate trade, and had another fleet formed to fight piracy in the Mediterranean. In his will he advised that the borders of the Roman Empire should be left as they were.

The northern and eastern land borders remained the key problem areas for ingress into the empire, as indeed they would until its demise. The lower reaches of both the Rhine and Danube favored defense and were more stable. It was the watershed mountains, their easily crossed upper reaches, and the gap between the two rivers that were particularly vulnerable. This is where the Roman defenses began to thicken incrementally. It took time for the frontier to stabilize, partly due to further advances. Each successive one left a discernible trace: Domitian furnished his with a clearly demarcated zone of watchtowers, fortlets, and redoubts supported by larger fortesses and linked by road. Further east in the Balkans persistent raiding by the Dacians, Suebi, and Sarmatians was left to Trajan to sort out.

Trajan strengthened the German defenses and in 101 attacked Dacia, determined to solve this decades-long problem once and for all. In fact it took him two attempts, but by 105, he had systematically reduced the Dacian fortresses, destroyed their capital, and brought their king’s head back to Rome. The conquest of Dacia produced a salient of territory north of the Danube whose strategic advantage was deemed worthwhile—but this part of the frontier had now become a central axis of the Roman military operations within the empire and sporadic fighting would continue until the territory’s defense proved too costly and Aurelian gave it up.

After Dacia, Trajan turned his attention to the east. In 114 he retook Armenia. In 115, he annexed northern Mesopotamia before going on to capture the Parthian capital, Ctesiphon. This was the high watermark of Roman operations in the area as trouble elsewhere in the empire demanded attention and Roman military resources were stretched. Trajan’s health was also failing and by 117 he was dead.

Trajan’s Column in Rome is a record of the emperor’s attacks on Dacia that led to it becoming part of the empire.

Timeline: 753BC–AD117

753BC Foundation of Rome.

509BC Creation of the Roman Republic.

c.390BC A taste of things to come. The Senones (an ancient Gallic tribe) defeated the Romans at the battle of Allia River, and then sacked most of Rome.

340–338BC Latin War: Rome fought the Latin League. Victory saw Rome annex a number of states and expand its territories considerably.

298–290BC Third Samnite War: Rome took control of the bulk of central Italy, in spite of the return of the Senones.

285–282BC Rome advanced into Gallic territory, defeating the Senones at Picenum (283BC), then a combined army of Gauls and Etruscans at Lake Vadimo (283BC), and finally the Etruscans at Populonia (282BC).

264–241BC First Punic War: Rome gained its first overseas possessions—Sicily became a province (in 241BC) and the breadbasket of Rome.

238BC Rome annexed Corsica and Sardinia, which became provinces in 238BC and 237BC respectively.

225BC Another Gallic tribe, the Boii, attacked Rome. They were destroyed first at the battle of Telamon and then at Clastidium in 222BC.

218–201BC Second Punic War: Rome became the Mediterranean superpower taking Carthaginian territories in Spain. In 197BC these became the provinces of Hispania Citerior (Nearer Spain) and Ulterior (Further Spain).

156–155BC Dalmatian Wars: after Illyria fell, the northern tribes—who went on to provide many Roman auxiliaries in the future—came into confli...