The Pax Romana: Its Rise and Decline

Angled shot of the Colosseum in Rome / Photo by Jimmy Walker, Wikimedia Commons

By Dr. Nicholas K. Rauh
Professor of Classics
Purdue University


Julio-Claudian Dynasty 27 BC – 68 AD

  • Augustus 27 BC – 14 AD
  • Tiberius 14 AD – 37 AD
  • Caligula 37-41
  • Claudius 41-54
  • Nero 54-68

Year of Four Emperors 69-70 AD

Flavian Dynasty 70-96 AD

  • Vespasian 70-79
  • Titus 79-81
  • Domitian 81-96

The Antonines 96-180 AD (the Five Good Emperors)

  • Nerva 96-98
  • Trajan 98-117
  • Hadrian 117-138
  • Antoninus Pius 138-161
  • Marcus Aurelius 161-180

Augustus of Prima Porta, 1st century / Vatican Museums via Wikimedia Commons

The Augustan Settlement proved to be a workable solution to the problem of imperial rule in theMediterranean. Utilizing a minimal central bureaucracy and rely at the local level on leadership in city councils, Augustus was able to enact legislation and to maintain order for a broad and diverse population. He channeled the aggressive energy of the Roman oligarchy to useful pursuits. He ended the abuse of corrupt governors and kept the armies under control. In addition, he reduced the tax burden on the Roman provincials. Through wise use of tax revenues he was able to intervene at the local level throughout the Mediterranean world to assist with calamities such as earthquakes in theAegean and the lack of food in the burgeoning city of Rome. He established the precedent of doing “more with less” that became the model for his successors. The one problem that he failed to resolve was a suitable means of succession. Instead of constructing some constitutional process for succession he fell back on more traditional practices of Roman patronage (i.e., the Roman family structure) and selected and groomed members of his immediate family to assume his place. This led to inevitable jockeying for position within the imperial family, known today as the Julio-Claudian dynasty, as well as to reports of conspiracies, intrigues, and assassinations. Roman sources paint his wife, Livia. in a very poor light for attempting to secure the throne for her son by a previous marriage, Tiberius Claudius Nero, allegedly by poisoning family members more directly in line for the throne.

In any event, Tiberius succeeded Augustus in 14 AD and proved by and large to be an effective administrator, however unpleasant and morose he was as an individual. He was succeeded in turn by a madman, his grand nephew Gaius or Caligula. Caligula attempted to humiliate whole segments of the Roman leadership cadres, the Senate, the Knights, the army, in a deranged effort to assert his notion of personal divinity. After his assassination, he was followed by his uncle, Claudius. This older man was entirely untrained for imperial rule because he suffered from birth from severe physical disabilities and had been kept out of the public eye. However, even this scholarly emperor proved to be a highly effective, if quirky, administrator. He was followed in turn by his step-son and grand nephew Nero. Having received the best possible education from the celebrated Roman philosopher, Seneca, it was hoped by all that this young emperor would emerge as the greatest ruler of the dynasty. However, he proved to be disinterested in the business of government.  Left to his own devices by Seneca and his mother, Nero developed interests in theater, music, dance, and the arts. He saw himself as the world’s greatest performance artist and began to put on shows not only inRome but in Olympia in Greece. Like Caligula, his extravagances and atrocities made him unpopular and his eventual purges of provincial military commanders incited rebellions. With his death in 68 AD the first Roman imperial dynasty came to an end. A civil war determined imperial succession and reminded the Roman world once again of the “bad old days” of the Late Republic.

The remarkable thing about these developments was that the solution became once again to restore Augustus’ “power-sharing” relationship between the Princeps, the Senate, and the Military Commanders on the frontiers. In short, the constitutional architecture of Augustus survived both madmen at the helm and internal civil war to provide a lasting model for organizing the resources and human power of the Mediterranean world. In many respects, the complaints of Roman sources against the Julio-Claudians ring hollow. Effective administrators such as Tiberius and Claudius appear to have been disliked primarily because they made the aristocracy pay its fair share of taxes and because they treated the lower orders of Roman society with greater equity. Even the least effective emperors, Caligula and Nero, were wildly popular with the Roman people and the provincials. This suggests that the Roman aristocracy alone suffered as a direct result of its close proximity to the seat of power. The further removed one was from the power struggles of the imperial dynasty, the better life became. This development stands in the inverse proportion to that of the Late Republic. One could even argue that the Roman aristocracy was merely receiving its just dessert after years of abuse and the misuse of power.

The Augustan Settlement proved successful in a number of other ways. It stabilized the military situation and brought accountability and order in the provinces. Roman army generals were selected for command directly by the emperor and worked on his behalf. Increasingly, the Roman legions became based on the borders of Roman territory, far removed from the urban populations, in order to confront neighboring barbarian peoples such as Germanic tribes north of the Rhine and Danube. Eventually, the legions became settled into permanent army camps along the limes — a line of natural and man-made barriers that defined the boundaries of the Roman Empire. These included the entire length of the Rhine and Danube Rivers in the north. Augustus likewise curbed the abuses of Roman provincial governors and Roman tax collectors in pacified regions. An end to the constant demands for excessive taxes and military requisitions meant that the provincials were able to keep more of their earnings for themselves. One theory holds that despite the imposition of the Roman tithe (approximately 10%), productivity in the Roman Mediterranean actually expanded at this time. Wealthy provincials expanded production in order to reap higher profits over and above the outlay of tithe. With peace and stability guaranteed, people began to invest more extensively in artisan and agricultural production, such as wine and oil for export purposes. The results can be seen in the material record: whereas, in the Late Republican Era (133-27 BC) some 8 to 10 internationally traded transport amphoras circulated throughout the Mediterranean, by the first century AD that number jumped to more than 40. So many amphora types were produced during the Roman Empire, in fact, that archaeologists have still not identified the points of origin for all of them.

Roman amphorae at Bodrum castle (Turkey) / Photo by Ad Meskens, Wikimedia Commons

Since transport amphoras were fashioned almost exclusively for shipment by sea they raise important questions about the scale of ancient Mediterranean shipping. To some degree this question can be addressed by the remains of ancient Mediterranean shipwrecks. By 1992 some 1189 ancient shipwrecks were recorded and published for the Mediterranean region. By and large, shipwrecks dated to the four centuries between 200 BC and 200 AD vastly predominate the available data of the Mediterranean and suggest in a negative manner that this period marked a peak era with respect to the relative volume of Mediterranean maritime trade. Most ships were relatively small, under 75 metric tons or 1500 amphoras capacity. The largest class of wrecks possessed dead load tonnage in excess of 250 tons or 6000 amphoras. These date mostly to the second and first centuries BC with a few additional wrecks recorded during the early Empire (first to second centuries AD). The data suggests that small cargo ships furnished the mainstay of Mediterranean trade, but that during period of the Roman Republic and Early Empire larger and larger cargo ships plied the waters of the Mediterranean and probably those of the Indian Ocean as well. Most of the shipwrecks of this period (78 of 98 or 81% of the total sampled) carried two or less categories of goods, mainly amphoras. Not only does this data stress the relative importance of transport amphoras as evidence of Mediterranean maritime commerce but it also suggests, however crudely, that commodities conveyed in amphoras formed the bulk of Roman commerce. Equally importantly, the existence of so many large “bulk” cargoes of one or two categories of goods indicates that at least during the period in question prearranged shipment of goods on consignment prevailed over “cabotage” or small-scale itinerant “peddling” of merchandise from port to port.

As the shipwreck data indicates, the greater portion of Mediterranean shipping is presumed to have transpired in relatively small vessels of 300 tons capacity or less. The maritime topography of the Mediterranean all but required this, since harbors with deep draft capacity were relatively few. The smaller carrying capacity of most Mediterranean cargo ships likely means that the number of vessels at sea at any one time was probably quite large. A recent estimate of Mediterranean shipping during the early medieval era posits that something in excess of 5000 cargo ships sailed the eastern Mediterranean waters during the sixth century AD. The combined shipwreck and literary data for the Roman Mediterranean era suggests that a considerably greater number would have been active during the early empire. In fact, the available evidence indicates that the volume of trade that occurred in the Mediterranean during the Roman era was the largest ever experienced in the ancient world. Converging forms of evidence indicates that this trade trended eastward across the Mediterranean to the Indian Ocean, raising important questions about the extent to which macroregional trade stimulated rising productivity in the Mediterranean basin.

The hypothesized result of so much economic activity was a gradually rising curve in material production throughout the Mediterranean at this time. Some scholars argue that productivity attained its peak during the second century AD, and that it stood at a level unmatched anywhere in the globe until the rise of nation states in Early Modern Europe (c. 1600 AD). Why the ancient Mediterranean economy failed to attain the “technological leap” beyond “human and animal power” to an “industrial revolution” remains an important question. This seems particularly so when it is clear that Hellenistic scientists such as Archimedes understood the principle of steam power and the Romans utilized principles of gravity to drive their aqueducts. The answer would appear to lie with the limited dissemination of recursive institutions in Roman Mediterranean society and the unwillingness of the aristocratic elite to engage in pursuits beyond, “religion, politics, and war.” During antiquity the most educated elements viewed anything associated with physical labor as beneath their station in life; hence, they did not apply their energies to the development of labor saving devices. Moreover, the inherent constituency of modern “research and development” was nonexistent in the ancient world. A broad-based educated public capable of absorbing new ideas or devising suitable applications for them was simply non existent. With so few educated people in antiquity even interested in “engineering” the likelihood of technological innovations remained remote.

Nevertheless, the order achieved by the Augustan Settlement brought the greatest period of peace and prosperity to the broadest possible population base found anywhere in ancient times. Some 50 to 100 million people existed under the Pax Romana, “the Roman Peace.” For nearly 200 years there was but one brief civil war, no piracy, no slave revolts. People and goods could travel safely from one end of the Mediterranean to the other. Cities such as Rome and Alexandria burgeoned to more than 1 million residents. A score of lesser cities, including refounded colonies at Carthage andCorinth, blossomed to become important nodes of provincial hierarchy and trade. Rome itself became an open city inundated by upwardly mobile foreigners. Roman critiques complained that the “slime of the Orontes River in Syria was now oozing up the Tiber River to Rome.” This served as a pointed observation of the natural success of outsiders in such fields as philosophy, medicine, law, finance, accounting, and trade.

Perge’s agora, in modern-day Turkey / Photo by Carlos Delgado, Wikimedia Commons

Moreover, these same sources criticize the growing autonomy of Roman women. With the armies enlisted from volunteers, carefully supervised, and kept at considerable distance from peaceful centers of urban population, the dominant political and social status of the male warrior element of the Mediterranean declined. In many instances one can detect a growing disinterest on the part of wealthy males to bear the burden of local authority and serve on their city councils, or to assume costly priesthoods, or other forms of public philanthropy (Athenian liturgies, known in Latin as munera).  Increasingly, these obligations were assumed by female members of elite provincial families. Many surviving examples of urban infrastructure, such as the monumental gate and mile-long “water trough” of the Perge in Pamphylia, were paid for and constructed by women such as Plancia Magna of Perge.  In Rome proper, not only did imperial consorts such as Livia, Agrippina, and Messalina, obtain unprecedented authority by virtue of their proximity to the seat of imperial power, but women on the streets appear to have obtained greater autonomy as well. In their misogynistic attacks on women, Roman male sources list the reasons for their complaints. Roman women were experiencing greater personal and sexual autonomy; they were working publicly as lawyers, doctors, philosophers, rhetoricians, and teachers. They engaged in marriages of convenience to better control their personal assets and social freedom. To what degree this growing female autonomy extended beyond Rome remains difficult to determine, but evidence such as that provided by the example of Plancia Magna of Perge suggests that it was potentially widespread throughout urban Mediterranean society.

Most of all Roman rule enabled the assimilation of common or “mainstream” cultural values that had been assembled from the various constituent populations of the Mediterranean. The fusion of Greco-Roman culture across the Mediterranean world resulted in the development of a visible homogeneity of life. One could travel from Antioch in Syria to New Carthage in Spain and expect to see the same social and political institutions, not to mention, the same monumental infrastructure.The invention of concrete mortar around 100 BC reduced the labor required in building enterprises and greatly expanded the built environment of the Roman Mediterranean. Every major town boasted its temples, its council house, its basilica, its theater, its gymnasium, its stadium, its aqueduct, its bath complex, its porticoed thoroughfares, and in many places its amphitheater. Red-slipped Early Roman finewares such as Arretine ware, Gallic ware, and Eastern Sigillata wares, furnish similarly evidence of Mediterranean-wide uniformity in creature comfort. Like Roman era transport amphoras, these hard, glossy, well turned bowls, plates, and cups were produced in nearly every corner of the Mediterranean and shipped widely throughout the seas. They appear in large quantities in nearly every Roman era archaeological context (including trading ports in East Africa and southern India), causing archaeologists to marvel at the amount of “stuff” possessed by ordinary inhabitants of the Roman Mediterranean world. Ceramic production expanded equally in other directions that survive on the landscape, such as ceramic water pipes that fed quantities of fresh water in and waste water out of most Roman urban communities, and most particularly ceramic roof tiles that furnished a level of permanence to Mediterranean built environments. Archaeologists who encounter ceramic roof tiles in the remains of installations as menial and remote as livestock stables and remote mountain huts that could be occupied only part of the year (due to snowfall), come away from the field with a heightened appreciation for the scale and breadth of Roman infrastructure at all levels of society and the extent to which firing technology and ceramic production were employed in Roman society. Remains such as transport amphoras, red-slipped Roman fineware, water pipes, and roof tiles represent the surviving material remains of a productive economy and fail to account for the volume of trade in other commodities such as foodstuffs, textiles, or timber that were shipped around the Mediterranean at this time.

This is not to say that the Roman world was some ideal place to live. Slavery remained a crucial component of society. Increasingly, peace and stability caused Roman society to evolve into a two class society, with the wealthy and socially superior honestiores enjoying greater rights and privileges than the masses of humiliores. The prosperity of the imperial order remained relatively superficial in that any major calamity such as a massive earthquake or a civil war could convert imperial surpluses into deficits. Not all peoples found a home in the Roman order, as the repeated Jewish revolts of the first and second centuries AD make clear. Policing society in the northwestern provinces of Gaul and Britain imposed a significant drain on the Roman treasury, and the inhabitants there were far less inclined to assimilate mainstream Greco-Roman culture. Overall, it needs to be borne in mind that the Mediterranean offers one of the easiest climates of the globe for human habitation. The mild climate minimized need for heat and clothing, the non-clay, highly volcanic soils were easiest to cultivate, and the interior lake of the Mediterranean, with its land-locked waters and countervailing winds and currents, facilitated trade in ways inconceivable for land-based societies such as Han China. Given its minimal technological advantages, however, there is no denying the remarkably accomplished impact Greco-Roman society had on its environment. Roman practicality and its engineering feats brought a consistently high standard of life to the Mediterranean world.


  • The Severan Dynasty 193-211
  • The Era of the Barracks Emperors 235-284 AD:
  • Diocletian, 284-305
  • Constantine 306-337
  • Theodosius I 378-395
  • Romulus Augustulus (last Roman Emperor in the West) 475-476
  • Justinian I 527-565

The Severan Tondo, depicting Septimius Severus and most of his family. / Photo by José Luiz Bernardes Ribeiro, Altes Museum, Wikimedia Commons

As prosperous as conditions appeared in 180 AD, conditions in the Roman Empire turned decidedlychaotic within fifty years. Some would point to slightly earlier indicators such as the plague which accompanied the return of Marcus Aurelius and his troops from his campaigns against the Parthians in Mesopotamia in ca. 166 AD. The plague (possibly small pox) appears to have wreaked a catastrophic effect on regional populations, possibly eliminating 25% of the Mediterranean work force. This was followed on quickly by Germanic invasions that pushed all the way to Aquileia on the Adriatic coast in 169 AD. The grasp of the imperial bureaucracy in Rome on the wider situation began to slip, particularly when directed by ineffective rulers such as M. Aurelius’ son, Commodus (180-192), who like Caligula and Nero in an earlier era, suffered from delusions of grandeur and proved unfit to rule. After his assassination civil wars erupted across the empire. By this time the armies based in separate, remote corners of the empire increasingly identified themselves with the provincial commanders they directly served, as opposed to the anonymous, distant hierarchy at Rome. Supported by their armies along the frontiers, several ambitious military commanders claimed the throne, setting in motion a violent struggle for succession. The eventual victor was a military strongman, L. Septimius Severus (193-211 AD). Starting from his command in Pannonia on the Danube frontier, Severus exhausted nearly four years combating rivals from Britain to Asia Minor. He then marched into northern Mesopotamia to suppress further uprisings. His long brutal march to imperial authority in Rome (culminating in purges of the senatorial aristocracy) furnished a hint of what was to come. Severus had little patience with the politics of the urban aristocracy at Rome and treated the Senate with a soldier’s mixture of disdain and intimidation. He also worked to solidify his support throughout the military by raising pay levels for the rank and file and by setting in motion a reorganization of the army as well as of the provincial structure. These measures served as a blueprint for later reformers. To make the Roman army more mobile, he adapted the army to cavalry formations and reduced the size of legions to 1000 men, while expanding the number of legions from 25 to 60. This made the army more responsive to the asymmetrical character of warfare on the perimeter, for example, the swift cavalry assaults of the Persians or the constant leakage of small bands of Germanic warriors across the frontier. By the end of his dynasty the Severans(Septimius and his sons Caracalla and Geta) had doubled the size of the army (from ca. 150,000 to 300,000).  Obviously, this raised the cost of military maintenance that had to be borne by tax-paying citizens and provincials. In a “sleight of hand” maneuver, Caracalla heightened the potential for tax revenues by extending Roman citizenship to all freeborn inhabitants of the empire (212 AD). This had the effect of making all inhabitants liable for the 10% manumission tax and 5% inheritance tax, including Roman citizens previously exempt because they lived in the provinces. Romans and provincials alike fell into the same tax burden with the imperial bureaucracy focusing particularly on the members of the city councils (the decuriones, or ten-man boards of local tax collectors) to make up shortfalls from their own assets if need be.

Septimius eradicated senators altogether from the provincial administration by replacing officers of senatorial rank with Knights (equites). By this era the equites were professional soldiers risen from ranks as low as centurions. To secure command and control of the provincial administration he inserted these replacements at the lowest possible level of the administration, namely, the diocese (in Latin, the conventus, or assize district). Not only did this insure that military officers loyal to himself controlled the provinces (and thus prevented further likelihood of rebellion) but it also meant that his newly organized military establishment could monitor and control production at the local level by imposing an aura of military efficiency. Resistance either from above or below would henceforth be difficult. Even the titles assigned to these commanders, praefectus legati agens vices legati for the military positions (“prefects acting as legates in place of legates”) and procuratores agens vices vicarii for the civil posts (“procurators acting temporarily in place of the previously temporary officials”), demonstrate the evolving character of a government in transition. The traditional provincial system yielded way to a network of 120 dioceses. Temporary titles such as praefecust, praeses, and vicarius, came to assume permanent significance.

Although Severus momentarily put the lid on crises, imperial stability quickly came unhinged following the death of the Emperor Severus Alexander (222-235 AD). During the fifty year interval between 235 and 284 AD some 24 emperors – known as the “Barracks Emperors” –  ascended the Roman imperial throne. The longest reigns were of seven and eight years respectively and all but two of these emperors died violent deaths. The emperor Decius was killed in 251 AD by the Goths on the Dacian frontier; the emperor Valerian, who posted the longest reign of eight years, was defeated and captured by the Sassanid King Shapur I in Mesopotamia (260 AD). Most of the others were assassinated. Civil wars, Germanic invasions along the northern limes, the secession of border provinces (Palmyra during 270s AD), and mounting pressure by the Sassanids in the East (260-651 AD) threatened the security and stability of the empire. To meet the challenges military men typically rising from humble origins in barracks communities along the frontier assumed the throne. Valerian (253-260 AD), Diocletian (284-305), and Justin (518-527), for example, all emerged from the Danube frontier where the Germanic threat was the greatest. Experiencing first hand the effectiveness of the Germans as warriors, these and generals like them began to recruit Germans openly into the ranks. By the late third century AD the army on the Rhine River was prevailingly Germanic in origin. In other words, an army that had already grown remote from and indifferent to the concerns of the inhabitants of the empire now increasingly replenished its ranks with foreigners who viewed Roman inhabitants as aliens.

After an orgy of violence and confusion, order was restored temporarily by Diocletian (284-305 AD). By this time the face of the imperial bureaucracy had assumed a decidedly military complexion. Imperial authority amounted to dictatorship with a bureaucracy geared toward administering a perpetual military emergency. Diocletian’s Price Edict attempted to dictate the fair value of goods and services. By this point the size of the army had possibly surpassed 500,000, imposing an impossible burden on the tax-paying citizens. To insure the necessary production to maintain the military establishment, all members of society were essentially locked into their stations in life, including members of the city councils. The son of a Decurion had to assume his father’s position in the council, just as the son of a tradesman or farmer had to assume their resprective places in the economic order. Some trades such as merchants were declared exempt from imperial obligations, but the designation of such exemptions carried with it the implication that they could also be taken away. The only way to escape the burdensome demands and requisitions of the new era was to be a member of the imperial bureaucracy itself. This led to a flight of elite elements from the provincial city councils, leaving the burden even heavier for those who remained. Imperial officials stationed at the local level were better positioned to collect tax revenues in kind and to see that they be shipped to nearby military forces. The subtle transition from a market-based to command economy is visible in the evolving form of transport amphoras. The amphoras of the Late Roman era lose their careful stylistic details to become nondescript, ruggedized jars and bottles, equally capable of being piled as much as stacked in the holds of cargo ships. They indicate a declining interest in the semiotic messages of consumerism (uniform, recognizable forms capable of advertising their contents) in favor of jars that are merely countable (and could thus verify that the tithe was being met) and capable of resisting the jostling of movement from place to place. This detail and others like it should not obscure the essential fact, however, that the military administration of the Late Roman Empire proved highly effective. Particularly in the eastern provinces amphora production in the newly organized diocesan system kept pace with the previous era, as did the production of red-slipped finewares, however ungainly both artifacts appear to the modern eye. Fineware production continued apace in red slip wares both in the east and in North Africa until the seventh century AD. The circulation of African Red Slipped wares produced along the Libyan coast show minimal decline even following the Vandal conquest of the region in 430 AD.  Building construction likewise kept pace in this era. All these details indicate that the population levels remained large particularly in the eastern provinces and that the military government made an essential effort to maintain the resources and stability of the empire.  Based on material remains, in other words, some archaeologists have characterized the decline in most regions of the Roman empire as a “slow burn.”

The tetrarchs (from the Greek words for “Four rules”) were the four co-rulers that governed the Roman Empire as long as Diocletian’s reform lasted. Here they were portraied embracing, in sign of harmony, in a porphyry sculpture dating from the 4th century, produced in Asia Minor, today on a corner of Saint Mark’s in Venice, next to the “Porta della Carta”. / Photo by Nino Barbieri, Wikimedia Commons

The external threats confronting Diocletian were real nonetheless, and Rome as a capital was too far removed from the areas of military concern. The emperor and his field army needed to be closer to the frontiers because it took too long to reach a crisis from the capital. Milan in northern Italy increasingly became the chief staging ground of imperial response to Germanic threats, but with the renewed vigor of the Sassanid threat in the East, even this position was untenable. Diocletian accordingly moved his palace first to Split in Dalmatia and then to Nicomedia in Bythinia. To stem the tide of the seemingly relentless civil wars among military commanders and to deal with the external threats on all quarters, Diocletian divided the empire into four prefectures, the Oriens, Illyricum, Italia, Galliae (all the Gauls). A Tetrarchy of four emperors, two ranked at the top as Augusti, two waiting in succession as Caesars, would command the regions and regularize the succession process (or so it was hoped). In 305AD after a 20 year reign, Diocletian insisted on a simultaneous abdication of himself and his Augustan colleague, Maximian. Almost instantaneously the move created a succession crisis, when the sons of the two Caesars, Constantine in Britain andMaxentius in Rome were passed over in favor of appointees by Diocletian. Haled by their troops as emperors, the two generals mutinied and fought a civil war that was resolved in Constantine’s favor in 312 AD at the Battle of the Mulvian Bridge in Rome. Although it required another twelve years to secure his place, Constantine (306-337 AD) eventually succeeded at making himself sole emperor of the Roman world.

Constantine is mainly known for his promotion and guidance of Christianity, which until now was a banned religious cult that had endured repeated waves of persecution including a recent, extremely violent purge by the Emperor Galerius (293-311 AD). Through his various edicts (Edict of Toleration, Edict of Milan, both in 313 AD), Constantine allowed Christians to practice their faith publicly and the church itself to acquire property. Christian clergy also became exempt from taxation. Having survived in hidden enclaves for centuries this sudden spotlight revealed the extent to which the faith had traveled in different directions around the empire. At the urging of bishops, Constantine convened several church councils (for example, the Council of Nicea 327 AD) to establish Christian dogma and a church hierarchy. These were dramatic steps taken on behalf of a religious population that is estimated at a relatively low 10% of the Mediterranean population at this time. The popularity of Christianity had spread to important places, however, such as the army, the provincial hierarchy, and even to the imperial household, where the wife of the Emperor Domitian (81-96 AD) and many of her servants were rumored to have been Christians.  The religion remained far from popular at Rome, the great capital and center of Roman state religion, where numerous temples dedicated to deified Roman emperors formed the backdrop to public affairs. Constantine completed the creeping movement of the hierarchy toward the frontier by relocating his imperial headquarters to the Greek harbor town of Byzantium on the Bosporus, thereby founding the new Christian capital of Constantinople. Closer in proximity to the threatened limes on the Danube and by road to the Sassanid frontier in Syria, this relocation of the capital prepared the ground not only for the creation of a built environment that featured Christian monuments, but also for the eventual bifurcation of the empire into East and West. It was not simply the distance of Constantinople from the West that brought this about but the disproportionate levels of manpower, resources, and attitudes that existed East and West. The eastern provinces were heavily populated, most productive, and more highly cultured. Surrounded by mountains, deserts, and seas, the eastern end of the empire was in many ways more compact and defensible. Extending across the Alps to the wintery landscapes of Gaul and Britain, the western provinces were more rural, less populated, and less inclined to absorb mainstream Greco-Roman culture. For centuries the revenues raised in the East had helped to sustain the cost of the military establishment defending the limes in the west. By moving the capital to Byzantium, therefore, even though this placed the imperial field army closer to the threats in the east (the Goths and the Sassanids), it essentially put the western provinces on notice. Incapable of resisting the threat of Germanic invasions, and with a defense comprised of a significant Germanic element itself, the western provinces yielded to renewed German invasions in less than a century following Constantine’s death. Already by the reign of Theodosius I (378-395 AD) it became customary to recognize a second emperor in the West and to leave him to his own devices, assuming the two leaders were even cooperating, a rarity in any event.

By the 370s AD a Hunnic faction that had split off from the Hsuing Nu in China began to intrude beyond the Caspian into the steppes of the Ukraine, ravaging Germanic tribes lying in its path such as the Alans. By 376 AD the Visigoths residing on the Danube border requested sanctuary from the Huns inside the Roman frontier and were allowed in. They were settled on land taken from Roman inhabitants as “submissive allies” (dediticii) and were expected to help buttress Roman defenses. Treated poorly by their hosts, however, they rose in rebellion and defeated the Roman army at the Battle of Adrianople (378 AD) and rampaged unopposed throughout the Balkans.  Led by their king, Alaric, they eventually migrated through Italy, where they shocked the Roman world by sacking the city of Rome in 410 AD. Few events could point more clearly to the collapse of the West than this. The Visigoths eventually settled in southern Gaul and Spain, but other invasions were already occurring. On Dec. 31, 406 AD, during a particularly cold winter the Rhine River froze over enabling some 50,000 Vandals to scamper across the ice. Dispersed in small warrior bands they successfully evaded Roman apprehension and migrated across Gaul and Spain to the edge of the Mediterranean Sea. By this point Roman authorities were so alarmed by the infiltration of German elements that the emperors issued orders not to allow the Germans to gain access to shipping. It was hoped that they could thus be contained at the northern end of the seas. But a general fighting a civil war in North Africa and in need of forces unwisely recruited the Vandals and transported them across the Strait of Gibraltar. Overwhelming their host they marched across North Africa and seized the city of Carthage in 430 AD. As it happened a Roman fleet lay at harbor and fell into their hands. They soon began to raid and plunder by sea, sacking Rome a second and far more devastating time in 455 AD. They got away with this partly because attention was directed elsewhere against the Huns, who invaded the Danube provinces around 440 AD and attempted unsuccessfully to besiege Constantinople. Attila then crossed the Rhine into Gaul. Defeated at the Battle of Chalons in 451 AD the Hunnic menace gradually declined, but the defeat would not have been possible without the assistance of Germanic tribes such as the Franks and the Burgundians, who now exploited the opportunity to settle in Gaul. By 476 AD, the Ostrogoths invaded Italy, forcing the German praetorian prefect, Odoacer, to depose the Romulus Augustulus, the last Roman emperor in the west. When the Ostrogothic King Theodoric (493-526) sought recognition as Roman authority in the West by the Roman emperor at Constantinople, his request was granted, thus officially sanctioning Germanic rule. The eastern empire remained resilient, however. Under the energetic emperor Justinian I (527-565 AD) Roman forces neutralized the Persian threat sufficiently to envision reconquering the West. Led by the impressive general Belisarius, Justinian’s forces retook Carthage, parts of Italy, Sicily, and coastal Spain. After a terribly costly siege they reentered the city of Rome itself. Known equally as much for his buildings (the Church of Haghia Sophia in Constantinople), his formulation of the Roman law code (the Corpus Iuris Civilis), and his marriage to his queen Theodora, Justinian’s ambitions overreached the eastern empire’s real capacities. At the slightest sign of difficulties with the Sassanids in the East, Justinian’s reconquest began to unravel. Troops being transferred from the Sassanid frontier to Italy brought with them the plague with devastating effect. Most of the reconquered territory was lost again to Germanic tribes such as the newly arriving Lombards in northern Italy. Within decades of Justinian’s reconquest, the eastern empire itself came under attack by Mohammaden Arabs in the East, and Slavic Avars and Bulgars on the Danube. Constantinople became a city under siege intermittently for decades at a time in the following century. Its imposing defenses and admirable water system (with urban cisterns the size of lakes) enabled it to outlast a succession of adversaries. Unlike the confident overwhelming force displayed by the armies of the Roman Republic when they conquered the Mediterranean world, the conquest of Justinian amounted to something of a gamble that ended disastrously and brought to an end all notions of a unified Roman Mediterranean world.

The archaeological evidence indicates significant material decline throughout the eastern Mediterranean in the seventh century AD. It is fair to ask why conditions declined so quickly.


  1. Inadequate Means of Succession. Roman historians traditionally point to the inadequate means of imperial succession as the first step in the crisis. Not only did Augustus fail to invent a “mechanical” means for succession, but it was probably inconceivable for the Roman aristocracy to conceive of succession by any other means than those dynastic. Family remained the basic building block of Roman society and even during the Era of Five Good Emperors, that was initiated by the “election” ofNerva with the consent of the Senate and the provincial governors, succession between Trajan and Hadrian, Hadrian and Antoninus Pius, Marcus Aurelius and Commodus, was ultimately dynastic. Constantine and Maxentius as the sons of Diocletian’s appointed “Caesars” fully expected to rise to their father’s positions dynastically and made trouble when their expectations were bypassed by Diocletian. The problems with dynastic succession are manifold, but the main one, what to do when the line dies out, inevitably provoked competition for the throne.
  2. The second cause was the Accelerating Pattern of Civil Wars that erupted at moments of imperial succession. Roman on Roman warfare ultimately was far more costly and burdensome than the external threats of the Germans and the Persians. Could the imperial hierarchy have found smoother means of transition and avoided the endless internal conflicts that racked the empire the external threats could possibly have been contained. The internal conflicts ultimately led to a doubling and then a second doubling in the size of the military establishment as well as to the recruitment of barbarian Germanic troops. The Augustan ideal of removing the armies to the limes had the advantage of eliminating violence in the “pacified” regions of the Mediterranean Sea, but it also led to a dislocation between the military, that identified with barracks communities along the frontier and gradually merged with the native populations, and the civilian inhabitants of the empire. Civilians and frequently even emperors such as Nero proved indifferent to the hardships faced by soldiers situated along the harsh frontiers of the empire. This provoked members of the military establishment to view themselves as a separate culture, and a highly resentful one at that. Already by the Year of the Four Emperors (79-80 AD), it became evident that ill will existed between armies based in different regions of the empire. In addition, rebellions led by Gallic auxiliary officers during that year of crisis demonstrated that the native populations in the West were neither as “pacified” nor as “assimilated” to Roman ways as people might have hoped. Command and control in the western provinces remained one situated in garrison towns with the constant threat of rebellion.  Once civil war became an option to enrichment, the armies, resenting each other, were very much on board with the new more violent program.
  3. The third reason often raised by historians for the fall of Rome was the Mounting Pressure of Barbarian Populations on the frontiers. In this respect, climate may have played a factor. Current climate models indicate that the Roman world was slightly warmer and wetter than it is today, making larger populations conceivable. It is possible that some fluctuation in temperature caused food shortages in the far north and set migrating peoples such as the Goths, the Vandals, the Franks, the Burgundians, and the Huns in motion. In addition, historical evidence of barbarian migrations of previous eras clearly demonstrate that the arc of these migrations frequently reached the shores of the Mediterranean (the Indo-European migrations in 2200-2000 BC; the Celtic migrations of the fourth century BC; the Germanic invasion of Italy in the late second century BC). By creating an impenetrable barrier (the limes) along the Rhine-Danube frontier the Romans attempted to interrupt what may have been a natural flow of migrating peoples and perhaps inadvertently heightened pressure along the frontiers than could only be stayed by building more defenses and larger armies until the dam finally burst in the fourth century AD.
  4. The need for greater military vigilance led to the fourth generally accepted argument, namely, that the Inordinate Cost of Maintaining So Large a Military Establishment proved too costly for what was essentially and agricultural society to bear. The burden of the rising military establishment is demonstrated economically in a number of ways: (a) the price Edict of Diocletian demonstrated the likely impact of devalued currency on the economy; (b) adaptations in amphora morphology appear to demonstrate a transition from commercial forms to those of a command economy; (c) the need to lock all producers into their stations, from the decurial class to ordinary farmers and artisans, indicates that if left unattended these roles would be abandoned; (d) various reports of flight by farmers abandoning land and city councilors fleeing their responsibilities are on record.

People fled to areas of asylum such as those provided by members of the military elite who enjoyed exemptions from taxation. This led to the emergence of vast private domains that embraced whole districts and numerous village settlements. People increasingly left their property to the Christian church which because of the exemptions awarded by Constantine could afford to rearrange agricultural production and landholdings on a more philanthropic order and ultimately emerged as the largest landowning institution in the Mediterranean. Regardless of the sequence in events the fact remains that the Roman Empire, like the Han Dynasty in China and the Guptas in India, proved unsustainable. The fact that all three civilizations hit a major snag at the end of the second century AD and ultimately collapsed by the sixth century has not gone unnoticed by world historians, who seek to identify some determining connection to chronology.