How did Theodosius the Great change the Roman Empire (2024)

A coin with a portrait of Theodosius I

Few remember the significant Roman Emperor, Theodosius I (345-392 AD). Theodosius I, or the ‘Great’ was the last Emperor to rule both in the Eastern and Western portions of the Roman Empire. He shaped the later years of the Roman Empire, he left an indelible mark on the Roman Empire's religion, and he more than anyone else turned it into a truly Christian Empire. Theodosius also helped to shape the nature of the Church and its relationship with the state.

These were to have profound implications for the successor states of the Roman Empire in the West. Theodosius helped to ensure that Christianity was the Empire's unchallenged religion, and this was to shape Europe and the Near East for centuries. Theodosius was instrumental in proscribing paganism, and he did much to destroy the ancient religions of the Roman Empire. He was also instrumental in stabilizing the Roman Empire after the disaster of Adrianople (378 AD). His peace agreement with the Goths was to have profound consequences for the Empire, both good and bad.


By the 370s AD, the Roman Empire was reasonably stable. However, it was clearly in demographic, economic, and military decline. Emperors ruled in the East and the West parts of the Empire, and they managed to hold it together. However, the borders were under pressure, and both halves of the Roman Empire were growing increasingly apart.[1]

Moreover, the Roman army was increasingly dependent on foreign barbarian mercenaries. These were mainly Germans, and they often lived within the borders of the Empire and had become very influential. The Empire was also divided on religious grounds, and there were many competing Christian sects and heresies that destabilized the Roman provinces. Such was the ferocity of the disputes between the various Christian groups that much of Egypt and North Africa were ungovernable.[2]

There was, also a great many pagans, and they resented the growth of Christian influence. In 376 A.D., a sudden influx of Goths and other German tribes crossed into the Balkans, fleeing from the fierce Huns. These German refugees destabilized the Roman Provinces in the region, and the Eastern Emperor was obliged to lead an army to contain the problem. Emperor Valens was an incompetent politician and an even worse general. He managed to antagonize the Goths and their allies, and this led to the Battle of Adrianople. This was one of the greatest defeats in Roman history.

Much of the army of the Eastern Empire was destroyed, and Emperor Valens was killed. This led to a crisis in the Roman Empire as a huge army of barbarians were pillaging and raiding freely and threatened Italy. In this desperate hour, the young Emperor Gratian of the West was facing another barbarian invasion and was forced to ask Theodosius to take charge of the East's situation, and he became Emperor.

Career of Theodosius I

Theodosius I with Bishop Ambrose of Milan, from a painting by Van Eyck, c. 17 century

Theodosius was born in modern Spain and came from a distinguished family. He had many years’ experience as a governor and a general and was considered the ideal choice to deal with the Goths. Theodosius first rebuilt the army, and in a series of maneuvers, he tried to contain the Germanic invaders. However, the Goths were ably led, and their army was growing as they recruited other barbarians and local bandits. He was also able to secure some reinforcements from Egypt. However, he was not strong enough to face the Goths in battle. Instead, the Eastern Emperor adopted the diplomatic approach. He entered negotiations with the Goths and defeated some hardline barbarian groups who did not want to negotiate. Finally, the Goths and the Romans signed a peace treaty. This allowed the Goths to govern themselves in a small area adjacent to the Danube.

The Germans and their allies had to serve in the legions if requested, and they had to protect the Danuban frontier. Theodosius managed to end the Gothic War, but it came at a cost. The Goths were given special privileges in the Balkans, which angered many local people who had suffered greatly at their hands. In Thessalonica, the population rioted against the presence of a Gothic garrison. Theodosius, I ordered the Goths to suppress the riot, and they did so with great fury and massacred thousands. The powerful Archbishop of Milan, Ambrose, excommunicated the Emperor, effectively expelling him from the Christian Church, because of the massacre.[3]

The Emperor was only re-admitted to the Church after several months of penance. This is often seen as a pivotal moment when the Christian Church in the West could overrule and even dominate the secular ruler. Theodosius, I was very much concerned with imposing unity on the Church, and he convened a series of Councils. He issued a series of edicts called the Theodosian Edicts that outlawed every creed other than the Nicene Creed. Theodosius was the first Christian Emperor to proscribe paganism and the famous Theodosian Decrees (379-382).

These abolished the old Roman religion's last remaining practices and branded pagan rites and beliefs as witchcraft. Despite the end of the Gothic War, the Empire was very unstable. The suspicious death of Emperor Gratian in the West led to the usurpation of the Western Provinces by general Maximus. He attempted to invade Italy but was defeated by Theodosius with the backing of the Goths.

However, Theodosius was not able to control the West. The Gothic General Arbogast quarreled with Theodosius, and the Goth set up a puppet Emperor in the West. Arbogast was an Arian Christian, and his puppet Eugenius was sympathetic to paganism and the old Roman religion.[4]. The rebellion, in part, was an attempt to overturn Theodosius' religious policy. However, Theodosius was able to defeat Arbogast and Eugenius at the Battle of Frigidus (394 AD). Theodosius became the sole emperor after his victory, but the unity of the Empire was to prove transitory. After Theodosius's death, the Empire was divided among his two sons, who were both ineffectual and dominated by barbarian generals.

How did Nicene Christianity become Roman State Religion?

Constantine had made Nicene Christianity the official doctrine of the Christian Church. However, since then, many Christian sects had appeared that disputed the veracity of the Nicene Creed. The Christian Church was divided among a series of groups who disagreed on the nature of Christ and his relationship to God. Arrian Christianity had become influential in the period before Theodosius I. The Emperor was a firm adherent of Nicene Christianity, and he effectively made it the state religion at the Council of Constantinople.

Theodosius, in an edict of 380 AD, proscribed all other forms of Christianity and deposed bishops who challenged the Nicene Creed. This did not immediately result in religious unity in the Church. However, it did lead to a decline in the influence of groups such as the Arians. Still, the Empire was to continue to be destabilized by religious divisions in the Church. However, by making the Nicene Creed the state religion, Theodosius ensured that the Christian Church adopted the doctrine. The Nicene Creed is the accepted creed of the vast majority of Christians sects to this day.

How did Theodosius abolish Paganism in the Roman Empire?

Between 389-392 AD, the Emperor promulgated a series of decrees that abolished paganism's last vestiges. This led to a series of anti-pagan measures that many regards as Christian persecution of pagans. He banned pagan rituals, sacrifices, and oracles. There were no longer to be any public expressions of paganism in any form. The Emperor also ordered every magistrate to rigorously enforce his measures or face prosecution and loss of office.[5]

Theodosius, because of his decrees, came into conflict with the still mainly pagan Roman Senate. He faced down the senators in a dispute over the restoration of the Statute of Victory in Rome. Theodosius forbade this, and this marked the end of any opposition to his anti-pagan measures. Theodosius, after his victory at the Battle of Frigidus, waged an open war against paganism. The defeat o Eugenius was the last attempt to resist the Christianization of the Empire.

In the wake of the victory, local bishops often led crowds to attacks pagan temples. Many of the ancient world’s greatest marvels, such as the Temple of Delphi, were destroyed. Around this time, the Ancient Olympic Games, which were part of a religious festival, were also suppressed. Many temples were also sacked in Egypt and Syria.[6] The Emperor either connived at these actions or failed to defend the pagans.

The campaign against the pagans was important, and it dealt a serious blow to paganism. All forms of the old Roman and other religions disappeared from the urban centers. It should be noted that paganism survived in many rural areas for centuries and that pagan practices, often regarded as witchcraft, persisted until the early modern period all over Europe.

What was Theodosius' policy towards the Goths?

Gothic soldiers from a contemporary engraving c.4th century AD

The most problematic aspect of Theodosius' legacy was his policy towards the Goths. He did manage to reach an agreement with the Goths and ended the war. However, the Goths remained very influential, and indeed the terms of the peace agreement meant that they began to dominate many Roman legions. The Goths became so powerful that they became a state within a state. Theodosius, after the catastrophe of Adrianople, had little option. He was not militarily strong enough to defeat the Goths in battle. He was forced to compromise with the Goths, and in doing so, he weakened his own and his son’s power.

Theodosius had only a small army of recruits and old soldiers called out of retirement. It is possible that if Theodosius had not ended the Gothic War, then the invaders could have destroyed the Empire. Furthermore, the Roman Emperor was only adopting a policy that was previously used successfully by other Emperors. Constantine had adopted a similar policy when some 300,000 Sarmatians entered the Empire earlier in the century.[7]

In the following century, the Goths became stronger and stronger, and after 400, they invaded Italy. In 410, a Gothic and allied army sacked Rome. It could be argued that if Theodosius had not compromised with the Goths and had done more to contain them, it would not have occurred. [8] This was something that could not have been foreseen by Theodosius, and even if he had, he could not have done anything else in the 380’s A.D.

Some argue that Theodosius' diplomatic approach to the Goths was a success and helped them buy some time for the Eastern Roman Empire. The peace treaty with the German invaders allowed a measure of peace to return to the Balkans and possibly even saved Constantinople. Theodosius, it is argued, helped save the Western Empire. He did much to allow the Eastern Empire to survive. This was very important as the Eastern Empire was able to evolve into the Byzantine Empire, which has had a decisive influence on Eastern Europe and kept the Arabs out of Europe.

What was the legacy of Theodosius?

The legacy of Theodosius is of enormous historical significance. He was the Emperor who ensured that the Roman Empire was truly Christian. He initiated a series of measures that resulted in paganism in many areas of the Empire. Theodosius was also responsible for the Nicene Creed to become the state religion. This changed the Early Church's character and meant that many rival creeds such as the Arian eventually disappeared over time.[9] This was to have immense repercussions for the development of Christianity and, given the importance of religion, on the evolution of European society and culture.

Theodosius inherited a disaster after the Roman defeat at Adrianople. He was forced to negotiate with the Goths and make many concessions to end the Gothic War. However, this weakened the Empire and contributed to the fall of Rome in 410 AD. On the other hand, Theodosius' policy may have helped secure the future of the Eastern Empire, which was to continue in some form or other until 1453. Theodosius was an important and able Emperor, but it is doubtful that he warrants the title of ‘Great.’


  1. King, N.Q. The Emperor Theodosius and the Establishment of Christianity (Pelican, London, 1961), p. 45
  2. Brown, Peter, The Rise of Western Christendom, 2003, p. 73–74
  3. Brown, p. 78
  4. Williams, Stephen and Friell, Gerard. Theodosius: The Empire at Bay (Yale, Yale University Press, 1995), p. 67
  5. Stephens and Friell, p. 113
  6. Stephens and Friell, p. 118
  7. Richard Brzezinski and Mariusz Mielczarek, The Sarmatians 600 BC-AD 450 (Oxford: Osprey Publishing, 2002), p. 145
  8. Heather, P. Goths, and Romans 332-489 (Oxford University Press; Oxford, 1991), p. 113
  9. Browne, p. 11
How did Theodosius the Great change the Roman Empire (2024)
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