After the reign of Diocletian, the Civil Wars of the Tetrarchy and the eventual accession of Constantine, which I wrote about in the post entitled “Constantine the Great and the Battle of the Milvian Bridge”, the empire was once again united. Constantine’s reign saw administrative and fiscal reforms and a series of victories against the barbarians; the Franks, Goths and Sarmatians all suffered defeats at the hands of Constantine’s armies and the empire was able to reclaim lost territories in Dacia and also re-establish firm borders.
However, by the end of the 4th century, events had changed once again. The sons and successors of Constantine had split the empire amongst themselves and had fought against one another, until only Constantius II remained.
He was unable to rule alone and re-established the idea of a co-Augustus, raising his relative Constantius Gallus to the purple.
Unfortunately, these two also clashed and Constantius was again involved in a series of wars, fisrt against Gallus and then against a succession of would-be usurpers.
Before Constantius’ death, his junior partner Julian was acclaimed as emperor by his legions in Gaul and this led to a resumption of war. However, Constantius died before engaging with Julian and, before he died, named Julian as his successor.
I will not dwell on the reign of Julian (known as The Apostate because he tried to return the empire to Paganism) or that of his short-lived successor Jovian.
Valentinian I, who had served under both Constantius and Julian, took the purple in 364 and ruled with his brother Valens as co-Augustus until his death in 375.
Valens ruled as Augustus of the East, with Gratian ruling the West (technically with his brother Valentinian II as a colleague), for another three years until his death at the hands of the Goths at the Battle of Adrianople in 378.
Although Gratian and Valentinian II were technically both co-rulers in the West, power remained with Gratian, because his half-brother was still only a child.
After the death of Valens, Gratian gave control of the armies of the East to Theodosius, a former Dux of Moesia, making him de facto ruler of the East.
Gratian and Theodosius pushed back the Goths and the Alemanni, inflicting major defeats on both confederations of barbarians, but over time, Gratian became lazy, preferring to spend his time pursuing pleasures and allowed the Frankish general Flavius Merobaudes to have huge influence in the Western empire.
Eventually, Gratian was killed in yet another rebellion and Valentinian II became sole ruler in the West.
Theodosius ruled in the East, until the death of Valentinian II in 392, when he assumed total control over both halves of the empire, becoming the last Roman Emperor who would ever rule as sole Augustus over both halves.
After the Battle of Adrianople, the Romans had increasingly suffered problems with the recruitment of troops. One effect of this was to increase the Army’s reliance on barbarians. Tribes had long served in the Roman army as auxiliaries but this was a new development, with Gothic and Germanic warriors being recruited en masse to supplement the shrunken ranks of the legions.
The post of magister militum, a kind of senior general of the troops, had been created by Constantine I and this role became increasingly important as the century progressed.
In the West, the position of magister militum came increasingly to be one that was in the hands of barbarians and it was one of these, Arbogast the Frank, who was implicated in the death of Valentinian II. This was to lead to yet another civil war between East and West, with Arbogast using his military power to create a Roman puppet emperor, one Eugenius.
The defeat of Arbogast and Eugenius by Theodosius allowed the empire to become unified again, however only for a short while, under Theodosius who was to die within the year, leaving the empire to his sons Arcadius in the East and Honorius in the West. Both of these were disastrous rulers, Arcadius was weak and was often manipulated by his wife Aelia Eudoxia and Honorius was only a child and was under the control of the Romanised Vandal magister militum, Stilicho.
I shall not dwell on the reign of Arcadius in the East at this point, because we are concerned with the business of the West.
Honorius’ rule was chaotic and saw the breakdown of Roman rule in many of the provinces of the West. Barbarian incursions increased, with Suevi, Alans, Vandals and Visigoths all invading, and there were revolts across the West, particularly in North Africa, Iberia and Britannia.
In 408, the Visigoth Alaric invaded Italy and besieged Rome, extorting a huge payment from the Senate to lift his siege. He returned in 410 and this time sacked the city.
The Romans were hampered throughout this period by three major factors.
Firstly, central rule was breaking down, with rebels declaring themselves Augustus in various provinces and establishing breakaway “empires”. Secondly, barbarian incursions became larger and the barbarians were staying inside the empire, rather than being pushed back. Thirdly, the government, such as it was, was unable to raise sufficient money from the reduced tax base to recruit new legions to replace those lost to usurpers and rebels or in battle against the tribes.
As a result, the Western army underwent a wholesale conversion to become a Germanic body of troops, officered by Germanic tribal leaders and with Romanised Germans at the highest levels of command.
Although the Western Empire was to survive for another 60 years or so, the seeds of collapse were sewn in the first two decades of the 5th century.
Power passed from the person of the Augustus into the hands of the military strongmen who vied for power and influence. These leaders, usually barbarians, were unable to rule themselves, but were able to make and break emperors as it suited them.
Wholesale immigration of barbarians into the Western empire effectively led to the setting up of independent fiefdoms within Roman provinces and the subsequent loss of tax revenue and eventually political control as well.
One can argue that a strong Augustus could have reversed the trends but, as I have discussed previously, the former Roman senatorial classes had disengaged from political life and the idea of loyalty to the emperor became less and less relevant in a fragmented West, with puppet emperors and barbarian general manipulating the political system. As more and more provinces became detached from the centre, it became less and less likely that the upper class of the Roman West would even wish to become involved in the chaos, with many of them transferring their support to regional strongmen.
The Emperors of the East were occupied with defending their own provinces from barbarian incursions and against the resurgent Sassanid Empire in the East to become embroiled in costly wars in the West.
Finally, in the early decades of the 5th century, we have to look at possibly the greatest barbarian threat that the Romans had yet faced at that time, the Huns.
I shall look at the Huns in Part 3 of this series.