Division of the Roman Empire (395): East and West Split

The division of the Roman Empire in AD 395 followed the death of Theodosius I on 17 January 395, when rule passed to his two young sons: Arcadius in the East and Honorius in the West. Shared rule was not new, but from this moment the two halves of the empire were never again governed by one resident emperor. The split shaped the separate fates of a Western empire that collapsed within a century and an Eastern empire that lasted until 1453.

Background: an empire too large for one ruler

By the 3rd century the Roman Empire stretched from Britain to Mesopotamia, and emperors struggled to defend several frontiers at once. Diocletian answered with the Tetrarchy in 293, a college of four rulers who each took charge of a region while the empire remained legally one.

Later emperors often divided responsibilities. Constantine reunited the empire under himself in 324 and founded Constantinople as a new capital in the East. In 364 Valentinian I gave the East to his brother Valens and kept the West, a division whose line was very close to that of 395.

Theodosius I, raised to power in the East in 379, became the senior emperor after the death of Gratian in 383. Only after defeating the Western usurper Eugenius at the Battle of the Frigidus in September 394 did he hold power over the entire empire. He enjoyed this for barely four months.

The death of Theodosius

Theodosius died at Milan on 17 January 395, probably of an illness the sources describe as dropsy, at the age of 48. Both his sons already held the title of Augustus, or full emperor. Arcadius, born about 377, had been Augustus since 383 and was in Constantinople. Honorius, born on 9 September 384, had been made Augustus in 393 and was with his father in Milan.

There was no formal document of partition. The sons simply took over the territories and courts where they stood, following the line used since 364. Theodosius’s body was taken to Constantinople and buried in the Church of the Holy Apostles.

How the empire was divided

The Western court controlled Italy, Africa (except Egypt and Cyrenaica), Gaul, Spain, Britain and the western Balkans: the provinces of Pannonia, Noricum and Dalmatia. The Eastern court held Thrace, Macedonia and Greece, the lower Danube, Asia Minor, Syria, Palestine, Egypt and Cyrenaica.

The large Balkan prefecture of Illyricum was a point of dispute. Its eastern dioceses of Dacia and Macedonia went to Arcadius, but the Western general Stilicho claimed them for Honorius, and the issue poisoned relations for over a decade.

Many institutions stayed shared. Laws were in principle valid in both halves and issued in both emperors’ names, each half named one of the two annual consuls, and an emperor in one half could recognise or refuse a colleague in the other.

Ministers and rivalry

Neither son governed himself. In the West the real power was Stilicho, a general of Vandal descent married to Theodosius’s niece Serena. He claimed that the dying emperor had made him guardian of both sons, a claim the Eastern court rejected.

In Constantinople the praetorian prefect Rufinus dominated Arcadius until 27 November 395, when soldiers under the Gothic officer Gainas, returning from Stilicho’s army, killed him in front of the emperor. Power then passed to the eunuch Eutropius.

The rivalry between the two courts let the Gothic leader Alaric play one off against the other. The East appointed him a commander in Illyricum around 397, while the West fought him in Greece and later in Italy. This tension contributed directly to the Sack of Rome in 410.

Contemporary writers reflect this tension. The court poet Claudian, writing for Stilicho in the West, attacked Rufinus and Eutropius in bitter verse invectives, while Eastern authors portrayed Stilicho as an enemy of the state, which in 397 formally declared him a public enemy.

Two different paths

The halves had always differed. The East was more urban, more populous and wealthier, with Greek as its main language of culture, although Latin long remained the language of law and the army. The West was mostly Latin-speaking and more rural, with a richer senatorial aristocracy but a weaker tax base.

The East’s main enemy, Sasanian Persia, was a settled state with which treaties could be made, and Constantinople was almost impossible to capture. The West faced a long Rhine and Danube frontier and repeated invasions by Goths, Vandals, Suebi and Huns. It lost Britain around 410, much of Spain and Gaul in the following decades, and Africa to the Vandals in 439.

The last Western emperor was deposed in 476 (see Fall of the Western Roman Empire), while the Eastern empire, often called the Byzantine Empire by modern historians, continued for almost another thousand years.

How the two courts worked

Each half had its own complete government. There were separate praetorian prefects, treasuries, armies and palace staffs, and each court decided its own military priorities. The Eastern court sat permanently in Constantinople, while the Western court moved from Milan to Ravenna in 402, a city protected by marshes and with easy access to the sea.

Cooperation was possible but unreliable. The East sent troops and fleets to help the West on several occasions, including a large expedition in 468 against the Vandals in Africa that ended in disaster. On other occasions the East preferred to divert threats westward, for example by encouraging Gothic groups to leave the Balkans for Italy.

The East also asserted a growing claim to approve Western emperors. In 424–425 Theodosius II sent an army to install his young cousin Valentinian III in the West, and later Eastern emperors often refused to recognise Western rulers whom they had not approved.

Myths and facts

Myth: Theodosius deliberately split the empire into two states. No source records a formal partition. He left the empire to two co-emperors, as Roman custom allowed; contemporaries still spoke of one Roman Empire.

Myth: the division caused the fall of Rome. It was more a reflection of existing realities than a cause. Its effect was to make the West rely on its own weaker resources, with only occasional help from the East.

Fact: the split also had a long cultural legacy. The gradual drift between a Latin West and a Greek East later helped shape the separation of Catholic and Orthodox Christianity.

Key people

• Theodosius I (347–395): last emperor to rule the whole empire.
• Arcadius (c. 377–408): Eastern emperor from 395.
• Honorius (384–423): Western emperor from 395, who moved his court to Ravenna in 402.
• Stilicho (c. 359–408): Western commander-in-chief and regent, executed in 408.
• Rufinus: praetorian prefect of the East, killed in November 395.

Timeline

• 293: Diocletian sets up the Tetrarchy.
• 330: Constantinople inaugurated as a new capital.
• 364: Valentinian I and Valens divide the empire.
• 379, 19 January: Theodosius becomes emperor in the East.
• 394, 5–6 September: Battle of the Frigidus; Theodosius rules the whole empire.
• 395, 17 January: Theodosius dies at Milan; Arcadius and Honorius succeed.
• 395, 27 November: Rufinus is killed in Constantinople.
• 402: Honorius moves the Western court to Ravenna.
• 476: The last Western emperor is deposed.

Why it matters

The arrangement of 395 fixed the map of the late Roman world. It created the separate political histories of the Latin West and the Greek East, explains why Rome fell in Italy while surviving in Constantinople, and laid foundations for the later division of Europe into Catholic and Orthodox spheres.