Theodosius: Life, Accomplishments, Death, and More!

Emperor Theodosius, born in Cauca, Tarraconensis in AD 347, was a prominent Roman emperor known for his military and political achievements. His father, Theodosius the Elder, served as ‘Master of Horse’ under emperor Valentinian.

Early Life

During his formative years, Theodosius, who would later ascend as the Roman emperor, received an education fitting for his noble status. This education encompassed rhetoric, philosophy, and military tactics, essential for his future role in the fourth-century Roman Empire. These formative experiences were critical in preparing him for the complexities and challenges he would later face as emperor Theodosius.

READ MORE: The Roman Army and Roman Army Tactics

The future emperor Theodosius began his military career under his father’s command in AD 368 in Britain, actively participating in campaigns against the Picts and Scots. This period was instrumental in honing his military skills and deepening his understanding of Roman territory and the strategic nuances of the empire’s frontiers. His exposure to various barbarian tribes during these campaigns further enriched his military acumen.

Rising quickly through the ranks, he became the governor of Upper Moesia around AD 373, where he led significant campaigns against the Sarmatians, further solidifying his reputation within the Roman military hierarchy. However, in AD 375, an important moment occurred when his father, serving under the Western Roman emperor, was convicted of treason and executed. This event led to Theodosius’s exile in Spain, marking a temporary setback in his burgeoning career. Little did he know, this period of exile was just a prelude to his eventual rise as a significant figure in the Christian Church and the Roman Empire, shaping his destiny as the future Eastern Roman emperor.

Coming Back from Exile and Fighting with Barbarians

The turning point in Theodosius’s life came after the catastrophic defeat of Rome’s army at the Battle of Hadrianopolis in AD 378, where the Visigoths decimated the forces of the Eastern Roman emperor Valens. Emperor Gratian recalled Theodosius from exile in order to deal with the disastrous circumstances in the east.

Theodosius achieved remarkable success at dealing with what was a desperate situation along the Danube. As a reward for his troubles, Gratian elevated Theodosius to the rank of Augustus of the east on 19 January AD 379.

In the immediate first years of his reign, Theodosius battled against the Visigoth forces and the barbarian settlers streaming across the Danube. But then he soon realized the task was an impossible one and in AD 382 he agreed on a treaty with them, making allies within the imperial borders.

The treaty allowed the Visigoths to live in Thrace on their own land, with their own laws and their own chiefs. Though, as part of the empire, they would be required to provide soldiers to the empire.

Also part of the treaty was the fact that Theodosius was required to make annual payments to the chieftains of these Visigothic tribes, to pay for troops they continued to command on his behalf. The barbarian tribes included in this treaty were by no way exclusively Visigothic. Other Germans and even some Huns were part of this agreement.

In a time of a desperate shortage of manpower in the army, the barbarians provided Theodosius with a ready source of fierce and skilled fighters, which not only enlarged his force but should gave him a decisive edge in his struggles with western usurpers to the Roman throne.

However, this enlarged army consumed enormous amounts of money. Theodosius showed even greater determination than Valentinian to increase the amounts he could obtain by taxation. He was determined that no one should own any property without having to pay tax for it. The laws which were passed to enforce this were so stringent that they led to widespread oppression.

The Peace of Acilisene

The Peace of Acilisene, a significant historical event, took place in AD 387, marking a pivotal moment in the late Roman Empire’s dealings with neighboring territories. This treaty was orchestrated between the Roman Empire and the Kingdom of Armenia, under the leadership of the Roman Emperor Theodosius I and the Armenian King Khosrov IV.

This peace agreement was rooted in the geopolitical struggles of the region, where Armenia had long been a contested zone between the Roman and Sassanian (Persian) Empires. The Peace of Acilisene represented a strategic diplomatic move by Theodosius I to strengthen the Roman position in this key area.

The treaty resulted in substantial territorial concessions from Armenia to the Roman Empire. A major component of the agreement was the ceding of the region of Acilisene to Rome, which was significant for its strategic location. This shift not only expanded Roman influence in the East but also secured a more defensible border against potential Persian incursions.

The cession of these territories altered the balance of power in the region, weakening the Armenian kingdom, which had functioned as a buffer state between the two great empires. It also had internal political repercussions within Armenia, affecting its future sovereignty and interactions with Rome and Persia.

For the Roman Empire, the Peace of Acilisene was emblematic of Theodosius I’s broader strategies to fortify the empire’s frontiers and manage its external relations through diplomatic means. This treaty underscored the complexities of Roman foreign policy during this period, characterized by a mix of military action, political negotiations, and territorial realignments.

Theodosius’ Relationship with Gratian

Theodosius’ relationship with his fellow emperor Gratian in the west was a strained one, largely on religious grounds, but the fact that Theodosius’ father had been executed under Gratian will surely not have made for friendly relations.

But when Magnus Maximus usurped the western throne in AD 383, Theodosius only reluctantly granted him recognition. Largely this recognition was only due to worries about Maximus’ ambitions against Gratian’s young co-Augustus Valentinian II in Italy. By acknowledging Maximus, Theodosius managed to persuade the usurper to recognize Valentinian II.

Meanwhile, Theodosius promoted his own son Arcadius to co-Augustus of the east in AD 383. When in AD 387 Maximus invaded Italy in order to dispose of Valentinian II, Theodosius led an army against him. The eastern emperor’s German and Hun troops helped him defeat Maximus at Siscia and then at Poetovio. Maximus was beheaded in Aquileia (AD 387). Thereafter Theodosius stayed in Italy until AD 391 effectively acting as sole emperor, despite reinstalling Valentinian II as western Augustus.

Being stern on matters of law and taxation, then on religious grounds, too, Theodosius became seen as a hardliner. Christian heretics were repressed with a series of new laws, at a time when even actual religious discussion itself was outlawed.

READ MORE: How Did Christianity Spread: Origins, Expansion, and Impact 

Theodosius’ Excommunication

Emperor Theodosius was excommunicated in AD 390 due to his harsh response to a civil disturbance in Thessalonica. The incident that led to his excommunication began when the citizens of Thessalonica lynched the Roman military commander, or ‘Master of Soldiers’, stationed in their city. In retaliation, Theodosius ordered a severe punishment, which resulted in a massacre of the city’s inhabitants. Only after Theodosius had done penance was he allowed back into the church. The excommunication was a truly historic event, as it showed the sheer power the church had gained by then.

The authority of the bishops was such that they could even enforce their will on the emperor. What followed was an enforced Christianization of the empire. In AD 391 pagan temples were closed and all of their worships were forbidden by threat of harsh punishment.

As Theodosius returned to Constantinople he left behind his ‘Master of Soldiers’ to assist Valentinian II in his rule of the west. But his faith in Arbogast proved a dire misjudgment of character. The overbearing Arbogast soon saw to it that Valentinian II was killed and created his own puppet emperor in Flavius Eugenius, who was a minister at the western court.

In AD 393 Theodosius promoted his second son, Honorius, to be the third Augustus in the east. Thereafter, once again, Theodosius needed to embark on a campaign to remove a usurper in the west (AD 394). On the river Frigidus he defeated Arbogast in AD 394 and thereafter had Eugenius executed.

Theodosius had in effect involuntarily re-united the two halves of the empire, though it was to be for a brief spell only. For already in January AD 395 Theodosius died at Mediolanum (Milan).

Emperor Theodosius’ Achievements

Emperor Theodosius I, also known as Theodosius the Great, is famous for several key achievements, such as completing the integration of the Christian faith in the empire, fighting off barbarians, and many reforms that had a lasting impact on the Roman Empire and the broader course of Western history.

  1. Finalizing the Christianization of the Roman Empire: Theodosius is renowned for making Christianity the official state religion of the Roman Empire. In AD 380, he issued the Edict of Thessalonica, which declared Nicene Christianity the state religion, effectively ending state support for pagan religions. This move was pivotal in the spread and establishment of Christianity as a dominant religion in the Western world.
  2. Battling Against Barbarian Invasions: Theodosius played a crucial role in managing the incursions of various barbarian tribes into Roman territories. Notably, after the devastating defeat of the Roman army by the Goths at the Battle of Adrianople in AD 378, Theodosius reorganized and strengthened the Roman military, managing to keep the Goths at bay and maintaining stability in the Eastern Roman Empire.
  3. Administrative and Military Reforms: He implemented significant reforms in the Roman military and administrative structures, adapting them to the changing needs of the empire and the new challenges it faced. This included recruiting and settling barbarian tribes within the empire’s borders as foederati (allied troops), a strategy that was both innovative and controversial.
  4. Reunification of the Roman Empire: For a brief period, Theodosius reunified the Eastern and Western Roman Empires under his rule. Following the death of Valentinian II, Theodosius became the sole ruler of both the Eastern and Western Roman Empires, a feat that had not been accomplished since the reign of Constantine the Great.
  5. Influencing the Future Division of the Roman Empire: Upon his death in AD 395, Theodosius divided the Roman Empire between his two sons, Arcadius and Honorius, which laid the groundwork for the eventual permanent split of the Roman Empire into Eastern and Western halves. The Eastern Roman Empire, or Byzantine Empire, continued for another thousand years, profoundly influencing the course of European and Middle Eastern history.
  6. Legislation and Social Policy: Theodosius enacted various laws that not only reinforced the Christianization of the empire but also addressed social and economic issues. His policies and legislations had a significant impact on the Roman legal system and societal structure.
  7. Role in Church-State Relations: Theodosius played a pivotal role in defining the relationship between the Christian Church and the Roman state. His reign is marked by close cooperation with church leaders and significant involvement in ecclesiastical matters, including the convening of the Council of Constantinople in AD 381, which affirmed the Nicene Creed.

Theodosius and Christianity

Emperor Theodosius I’s tenure was a transformative era for the Roman Empire, especially in the realm of religion. His profound influence on the religious landscape is marked by several key decisions and events that firmly established Christianity as the dominant faith within the empire.

Under Theodosius, Christianity rose from a tolerated religion to become the official state religion of the Roman Empire. The Edict of Thessalonica in AD 380 was a watershed moment in this transformation. This decree mandated that all Roman citizens should follow the faith as professed by the bishops of Rome and Alexandria, effectively endorsing Nicene Christianity. This edict marked a significant shift away from the empire’s traditional religious pluralism, signifying the end of state support for paganism and other religious practices.

Theodosius’s approach to paganism and heresy was marked by assertiveness. He actively worked to suppress pagan practices, closing temples and halting traditional rituals, including the Olympic Games, which had deep pagan associations. His reign also witnessed the destruction of several notable pagan sites. Concurrently, Theodosius took a firm stance against heretical movements within Christianity, aiming to establish a uniform Christian doctrine across his domains.

A pivotal event in Theodosius’s religious policy was the convening of the First Council of Constantinople in AD 381. This ecumenical council, the second in Christian history, played a critical role in cementing Christian orthodoxy. It expanded the Nicene Creed and addressed the Arian controversy, affirming the divinity of Jesus Christ. This council was a significant step in the development of early Christian doctrine and showcased Theodosius’s deep involvement in ecclesiastical matters.

Theodosius’s reign also marked a notable evolution in the relationship between the Church and the state. He worked in close alliance with prominent church leaders, such as Ambrose of Milan. His laws often reflected Christian values, focusing on moral and ethical standards that aligned with Christian teachings, including measures aimed at protecting the vulnerable.

A particularly notable incident in Theodosius’s reign was his excommunication by Bishop Ambrose following the massacre in Thessalonica in AD 390. This event underscored the growing power of the Church, as it demonstrated that even the emperor was subject to ecclesiastical authority. Theodosius’s subsequent public penance was a significant moment, highlighting the Church’s influence and the emperor’s willingness to submit to its authority.

In his final years, Theodosius continued to enforce Christianization, including closing pagan temples and forbidding pagan worship. These actions, coupled with his administrative and military reforms, not only shaped the religious contours of the late Roman Empire but also laid the groundwork for the religious character of medieval Europe.

The relationship between the Church and the state reached a new dynamic during Theodosius’s reign. He maintained close relationships with church leaders, notably Ambrose of Milan, and his policies often mirrored Christian morals and ethics, focusing on legislation that aligned with Christian teachings.

Converting to Christianity

Theodosius did not convert to Christianity because he was a Christian from birth. Born into a Christian family in AD 347, Theodosius was raised in the Christian faith, which significantly influenced his policies and reign. This is in contrast to his predecessor, Constantine the Great, who converted to Christianity during his rule. Theodosius’s lifelong commitment to Christianity played a key role in his decisions as emperor, further shaping the Christian legacy of the Roman Empire.

The Death of Theodosius

The end of emperor Theodosius I’s reign and his subsequent death marked a significant moment in the history of the Roman Empire. Theodosius, who had become a pivotal figure in the late 4th century, both politically and religiously, passed away on January 17, AD 395. His death occurred in Milan, known at the time as Mediolanum, a city that had witnessed many of his important decisions and interactions, especially with the Christian Church.

Theodosius’s death was not only the end of an era for the Roman Empire but also the beginning of a significant transition. His reign had been marked by numerous military, administrative, and religious achievements, including the definitive establishment of Christianity as the state religion, efforts to repel barbarian invasions, and the temporary reunification of the Eastern and Western Roman Empires.

His passing had profound implications for the future of the empire. In his final act as emperor, Theodosius divided the Roman Empire between his two sons: Arcadius, who was given control of the Eastern Roman Empire, and Honorius, who took over the Western Roman Empire. This division was intended to provide stable and manageable governance; however, it eventually led to the permanent split of the empire into Eastern and Western halves. The Eastern Empire, later known as the Byzantine Empire, continued to thrive for another thousand years, while the Western Empire faced increasing challenges and eventually fell in the 5th century.

Theodosius’s death also had significant religious implications. He had been a staunch defender and promoter of Nicene Christianity, and his policies had laid the groundwork for the religious character of medieval Europe. His passing was felt deeply within the Christian community, which had seen in him not just a political leader but a champion of their faith.

From Soldier to Saint: The Theodosian Transformation of Rome

Emperor Theodosius I’s reign stands as a cornerstone in the annals of Roman history, marked by his military prowess, diplomatic skill, and profound religious influence. His decisive actions, from the strategic alliances and reforms to the unwavering promotion of Nicene Christianity, not only shaped the Roman Empire’s immediate trajectory but also its enduring legacy.

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