San José State University
Department of Economics
Thayer Watkins
Silicon Valley
& Tornado Alley

The Economic History
of the Western Roman Empire

The Invasion of the Western Roman Empire
by Barbarian Tribes

The purpose of this document is to summarize the period of barbarian invasion of the western Roman Empire over the period from the third century A.D. to the fifth century. The primary source material is a series of lectures by J.B. Bury of the University of Cambridge which were published as The Invasion of Europe by the Barbarians. Professor Bury presented a coherent view of the invasions but his work was published in 1928 and some historical items, particularly in the early background material, may have been superceded by more recent findings. His book was reissued in 1963 without revision so any shortcomings of his work are not likely to be essential to his presentation. The barbarians that were most significant in the invasions were the Germans with a brief interlude of Hunnic penetration. The Slavic and Magyar migrations came after the period under consideration.

Background of the Germanic Peoples

In the period before 1000 B.C. the Germanic tribes lived in Scandinavia and the land between the Elbe and Oder Rivers. To the west of the Elbe River the land was occupied by Celtic people. To the east of the Oder River there were Baltic people such as the Letts and Lithuanians. Over the centuries the German tribes between the Elbe and the Oder pushed west driving the Celts out. By 200 B.C. the border between the Germans and the Celts was pushed to the Rhine River. The German tribes also pushed from the lowere Elbe region to the upper Elbe region occupying what is now southern Germany.

Some of the German tribes in Scandinavia migrated across the Baltic to the land between the Oder and the Vistula Rivers. This migration took place after the expansion of the western Germanic tribes from the Elbe-Oder region. These Germanic migrants from Scandinavia were different from the Germans of the Elbe-Oder region in language and customs but both had an economy originally based upon hunting and herding.

Population growth was forcing migratory expansion. When the western Germanic tribes, those originally from the Elbe-Oder region, ran out of territory that could easily be acquired their social and economic structure had to be modified. The area of north central Europe at that time was largely covered by forests. The herder-hunters needed areas relatively clear of forest. In the face of population growth there were only a few things that could be done:

These are listed in their order of difficulty. The western Germanic tribes ran out of territory because they impinged upon the Roman Empire on the west and the south. In the east they faced the descendants of the migrants from Scandinavia (who hereafter will be called the eastern Germanic tribes). The western Germanic tribes adopted agriculture.

In contrast the eastern Germanic tribes still had a migratory expansion option. They faced not the equally tough German people but Slavic and Baltic people who could not match their military prowess. Thus the eastern Germanic people continued their herding economy for centuries after the western Germanic people took up the practice of agriculture.

The most notable of the eastern Germanic tribes was the Goths. There is considerable historical evidence of the origin of the Goths in Scandinavia, possibly the Baltic island of Gotland, but in the second century A.D. the Goth moved from the lower Vistula River region to the area north of the Black Sea.

In the Black Sea region the Gothic tribes divided into two divisions, the Ostrogoths and the Visigoths. The name Ostrogoths means roughly the eastern Goths. Visigoth did not mean western Goths but, in effect, that is what they became.

Besides the Goths the other eastern Germanic tribes were the Vandals, the Gepids, the Burgundians and the Lombards, names that appear in the later history of western Europe far from their original homelands.

The western Germanic tribes were also undergoing political amalgamation and alignment. Tribal confederation names that are familiar from history are the Franks (meaning free as opposed to tribes settled in Roman territory), the Saxons, the Thuringians and the Alamanni. The Alamani were made up of Suevian tribes. The name for Germans in some languages of Europe is derived from the name Alamani.

The German tribes had political systems that were virtually democracies or republics. The assemblies of freemen of the tribe were sovreign. Some tribes were ruled by leaders who functioned as kings, but there was a difference even among tribal groups having kings as to the nature of the kingship. First of all the king was in effect the executive officer of the assembly of freemen of the tribe. Some tribes had leaders called grafs who were elected by their assemblies of freemen. A graf could be anyone the assembly wished to elect. The monarchical tribes had kings, who were also elected by the assemblies, but in contrast in the monarchical tribes or states the king had to be selected from certain royal families. Thus the kingship was to a degree hereditary whereas the grafship was not.

The Attacks of the Goths on the Roman Empire

It is ironic that the most serious threats to the Roman Empire began not with the western Germanic tribes of the Roman frontier but the eastern Germanic tribes, particularly the Goths. The Roman Empire during the early third century had a series of weak emperors and a strong challenge from the Parthian Empire of Persia. The resources of the Empire were debilitated and the Goths challenged the Romans for control of the area at the mouth of the Danube River at the Black Sea. The Goths controlled the area north of the Black Sea and the Romans had conquered a territory north of the Danube, which they called Dacia. This is the region of present day Romania.

The attacks of the Goths began in 247 A.D. and in 251 A.D. They lured the Roman army under the command of the Emperor Decius into a swampy region and defeated it. The Emperor Decius was killed in the battle. Emboldened by this victory the Goths built boats and ships and raided the cities of the Black Sea and eastern Mediterranean. The Romans under Claudius I finally were able to defeat the Goths decisively in 269 A.D. and brought peace to the region. The Emperor Claudius was thereafter known as Claudius Gothicus. But Claudius Gothicus' rule did not last long and he was succeeded by the Emperor Aurelian.

The Emperor Aurelian recognized the realities of the military situation in Dacia and in 270 A.D. withdrew Roman troops from Dacia leaving it to the Goths. The Danube once again became the northern frontier of the Roman Empire in eastern Europe. In 324 A.D. the Emperor Constantine concluded a treaty with the Visigoths that made them confederates of the Empire which meant that in return for annual subsidy the Visigoths agreed to help defend the Empire. Nominally Dacia was again counted as part of the Empire but controlled and defended by the Visigoths, confederates of the Roman Empire.

The Ostrogoths were located to the east of the Visigoths in the region beyond the Dniester River. There were significant differences between the Ostrogoths and the Visigoths, generally the Ostrogoths represented a more archaic form of Gothic society.

The Numbers of the Invading Tribes

It is difficult to estimate the number of barbarians involved in the invasisons but roughly there were one hundred thousand Ostrogoths in Italy and about the same number of Visigoths in Spain. The Burgundians in southeastern France probably numbered about twenty five thousand. The estimated size of the Vandal army which crossed the Strait of Gilbraltar is eighty thousand. Thus the invasion forces constituted only a few percent of the population of the territories being invaded. This was enough to conquer a non-military population but not enough to surplant the culture of the people being conquered.

There was also the non-Germanic people known as the Sarmatians or Alans. The Alans were the principal tribe of the Sarmatians. The Sarmations spoke a language in the Iranian language family. A Roman emperor brought Alans into southwest France to help control Celtic tribes and protect against Germanic invaders. For more on the Sarmatians see Sarmatians.

The challenges of the barbarians to the Empire imposed a heavy burden on its finances and its military. The burden of raising the troops and the funds to defend the Empire was threatening to bring about its collapse. The Emperor Diocletian undertook a major reorganization of the Empire. Later the Emperor Constantine undertook further political and economic reorganization.

The Organizational Structure
of the Roman Empire After the Reforms of the
Emperors Diocletian and Constantine

The above diagram depicts that fact that the Roman Empire was not divided into two seprate empires but instead was legally one empire with two administrative centers, Rome and Constantinople. These two administrative centers were governed by two co-equal emperors. The administrative authority in both sections was divided between a civil government structure and a military authority. The Roman Empire was unique in this separation of administration.

The civil government structures in the western and eastern portions of the Empire were identical, but the military power structures in the two portions differed in some details. The civil governmental structure was the basically the creation of the Emperor Diocletian, as was the division of the Empire into western and eastern administrations. The Empire was divided into prefectures each governed by ministers called praetorian prefects. As shown below, there were two prefectures in the east and two in the west. The prefectures were divided into dioceses, each ruled by a vicar. The terminology is familiar because the Roman Catholic Church adopted the organizational structure of the Roman Empire. The dioceses might be divided into provinces ruled by governors.

The composition of the prefectures was as follows:

The Structure of the Military Authority of the Empire was more complicated than the civil governmental structure. First there was a divsion between the troops stationed at the frontier, the Limitanei, and the mobile army, the Comitatus, which could be sent to trouble spots. Within the army there was an institutional distinction between the infantry and the cavalry. At the time of the barbarian invasions the infantry was the more important military force but this changed throughout history. At the time of Diocletian the cavalry was given an independent status but later came under the rule of the masters of the infantry. Both the infantry and the cavalry were under the authority of a master of the soldiers. In the eastern Empire there were five masters of the soldiers, two of which were located in Constantinople and were called masters in attendance of the emperor (Magistri in praesenti). The other three resided in important regions such as Thrace and Illyricum. In the west there were only two masters of the soldiers, both Magistri in praesenti, residing in Italy. One of these was master of the infantry and had command over both the infantry in the mobile army and the infantry in the guards stationed at the frontier, the limitanei. The other master of the soldiers in Italy had command over the cavalry of the mobile army.

The Problem of Military Manpower

J.B. Bury points out the problem the Roman Empire had with raising military manpower. Although the Empire had a population in the range of 50 to 70 million people it never had an army of over one million. In modern times nations often recruit an army equal to ten percent of the population. There is a constraint for modern armies imposed by the need for manpower in industries supplying munitions and equipment. This was not as much of a limitation for ancient armies and thus an ancient country could raise an army equal to several times as much as the ten percent proportion that limits modern armies. Thus the Roman Empire might have been expected to have been able to raise an army many times what it actually did. The problem, according to J.B. Bury, is that almost all of the males of the Roman Empire were unfit for hand-to-hand fighting against the barbarian enemies. They were not physcally fit enough and too civilized to cope with the uncivilized barbarians.

One of the few places that could supply suitable manpower for the army was the mountainous regions of the Balkan Peninsula. This area became an element of contention between the eastern and western Empire solely for its supply of suitable soldiers.

At first the German barbarians were excluded from the Roman army but over time the Empire recognized that the only match for the barbarian soldiers was barbarian soldiers fighting for the Empire. As Germans were admitted into the army in the western Empire and became the backbone of the fighting force the officers commanding them soon were Germans as well. As Germans moved up the command structure a major structural problem developed in the governing of the western Empire. The real power in the Empire came to reside in the German commanders in the army but these individuals were precluded because of their ancestry from holding the high offices in the civil government. This meant that if the German military leaders could not become the legal rulers of the administrative units the next best thing from the viewpoint of the German commanders of the Roman army was to have the civil offices held by weak, incompetent Romans.

(To be continued.)

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