Roman Empire of the East, 395-641: How the Eastern Half Survived and Changed

Contents15

• The Roman Empire of the East at a glance
• How the empire came to be divided
• Eastern emperors, 395-641
• Why the East survived the 5th century
• Generals and the Eastern court
• The East and the West, 395-476
• The economy of the East
• Constantinople: the New Rome
• Religion and the great councils
• Justinian's reconquests
• When did the Eastern Roman Empire become "Byzantine"
• Heraclius and the turning point of the 7th century
• Law and learning in the late Roman East
• The legacy of the eastern empire's first centuries
• Verdict: the Roman Empire of the East

The Roman Empire of the East is the eastern half of the Roman state after 395. That year Emperor Theodosius I split rule between his sons. From Constantinople the East ruled Greece, the Balkans, Anatolia, Syria, Palestine and Egypt.

When the Western half fell in the 400s, the East survived. This page covers its first 250 years. It runs from Arcadius in 395 to Heraclius in 641. By then it had become the state historians call Byzantine.

TL;DR: The Eastern Roman Empire began as a separate court in 395 under Arcadius. It survived the 400s thanks to its wealth, the walls of Constantinople and careful diplomacy. Justinian I (527-565) won back North Africa, Italy and part of Spain. Heraclius (610-641) beat Persia. Then he lost Syria and Egypt to the Arab conquests. Greek replaced Latin as the language of government.

The Roman Empire of the East at a glance

How the empire came to be divided

The Roman Empire had often been ruled by more than one emperor. Diocletian's Tetrarchy split it among four rulers from 293. Constantine's sons split it again after 337.

Theodosius I was the last emperor to rule the whole empire, briefly, in 394-395. He died in January 395. His elder son Arcadius took the East. His younger son Honorius took the West.

People at the time did not think of this as two empires. The Roman state was one, with two courts, two sets of officials and two armies. Laws issued in one half were in principle valid in the other. But after 395 the two halves never again came under one ruler.

Eastern emperors, 395-641

The complete list of later emperors, to 1453, is on the Byzantine Empire page.

Why the East survived the 5th century

The 400s brought the same pressures to both halves. Goths, Huns and other peoples pressed on the frontiers. Powerful generals held sway at court. The West fell, but the East did not. Historians usually point to four reasons.

• Wealth. The East held the richest provinces, above all Egypt, Syria and the cities of Asia Minor, and its tax revenue was higher.
• A fortress capital. Constantinople was surrounded on three sides by water. The Theodosian Walls, built on the land side from 413, made it almost impossible to storm for centuries.
• A shorter exposed frontier. Its most dangerous neighbour, Sasanian Persia, was a settled state that could be dealt with by treaty.
• Diplomacy and payment. Eastern emperors paid Attila and others to stay away, and at times encouraged invaders to move west.

The fall of the West, and when exactly it happened, is covered on the when did the Western Roman Empire fall page.

Generals and the Eastern court

The Eastern court faced the same danger as the Western one. Strong generals of non-Roman origin could control the emperor. The East managed to break their hold.

• Gainas, a Gothic commander, dominated Constantinople in 400 until a popular rising drove his troops out of the city.
• Aspar, an Alan general, was the leading power behind the throne for decades and helped make Leo I emperor in 457. Leo had him killed in 471.
• Zeno, himself from Isauria in southern Anatolia, relied on Isaurian soldiers as a counterweight to Germanic commanders.

By the end of the 400s, the East had largely freed itself from the army kingmakers who controlled the West.

The East and the West, 395-476

The two courts worked together at times and competed at others. The East sometimes sent troops and money to help the West. In 467 it sent Anthemius to Italy as Western emperor. In 468 it paid for most of a huge joint attack on the Vandals in North Africa.

It ended in disaster. Western emperors needed the East's backing. Those who lacked it, such as Libius Severus, were seen as weaker. After 476 the Eastern emperor Zeno became, in theory, the only Roman emperor.

The economy of the East

The East's wealth came from its rich farmland and its cities. Egypt's grain fed Constantinople. It was shipped each year across the Mediterranean.

Syria, Asia Minor and the Aegean had busy ports and markets. The empire also sat on trade routes to the Black Sea, Persia and India. Constantine brought in a gold coin, the solidus. It gave the East a stable currency for taxes and trade.

Constantinople: the New Rome

Constantine opened his new capital on 11 May 330. It stood on the site of the old Greek city of Byzantium. It had a senate, free grain and monuments modelled on those of Rome. The Council of Constantinople in 381 ranked its bishop second only to the bishop of Rome, "because it is New Rome". By the 500s the city was the largest in the Christian world.

Religion and the great councils

The Eastern empire was the centre of the early church's great debates about the nature of Christ. Emperors called church councils and presided over them.

The split after Chalcedon divided the empire's Christians for centuries. It weakened loyalty to Constantinople in Egypt and Syria.

Justinian's reconquests

Justinian I set out to win back the lost West. His general Belisarius destroyed the Vandal kingdom in North Africa in 533-534. The war against the Ostrogoths in Italy began in 535. It dragged on until the 550s and left Italy in ruins. Imperial forces also took part of southern Spain from the Visigoths in the 550s.

At home Justinian had Roman law gathered into one code. The work was done in 529-534, and it was later called the Corpus Juris Civilis. He rebuilt Hagia Sophia after the Nika riots of 532. His reign also saw the first known outbreak of bubonic plague, from 541.

When did the Eastern Roman Empire become "Byzantine"

Start of the "Byzantine" period

When the Eastern Roman Empire becomes "Byzantine".

Status: Disputed Historians use several different starting points.

Note: The empire's people never stopped calling themselves Romans. So any start date for a "Byzantine" period is a modern choice. Some historians begin with Constantine's founding of Constantinople in 330.

Some begin with the split of 395, and some with the end of the West in 476. Many begin in the 600s, when Greek replaced Latin in government and the Arab conquests reshaped the state. A recent Oxford history of Byzantium is titled "The New Roman Empire". It reflects the view that the state was Roman throughout.

Sources: Oxford Academic, "The New Roman Empire: A History of Byzantium"; Lumen Learning, "Naming of the Byzantine Empire".

Heraclius and the turning point of the 7th century

Heraclius came to power in 610, in the middle of a disastrous war with Persia. Persia had taken Syria, Palestine and Egypt. In a series of bold campaigns he invaded the Persian heartland. He forced a peace in 628 and won back the lost provinces.

The victory did not last. From the 630s Arab armies, united under Islam, attacked the worn-out empire. After the defeat at the Yarmuk in 636, Syria and Palestine were lost.

Egypt fell in the early 640s. The empire that survived was smaller and more Greek. Heraclius used the Greek title basileus, and Greek replaced Latin as the language of government.

Law and learning in the late Roman East

The eastern empire was the centre of Roman legal work in late antiquity. Theodosius II's code of 438 gathered the laws issued since Constantine. A century later, Justinian's team, led by the jurist Tribonian, made a far larger collection. It held laws, legal opinions and a textbook for students.

Constantinople also had a public school of higher learning. Theodosius II reorganised it in 425, with teachers of Latin and Greek, law and philosophy. Alexandria, Antioch and Beirut were other centres of learning. Beirut had a famous law school.

The legacy of the eastern empire's first centuries

The Eastern Roman Empire of 395-641 kept Roman law alive through Justinian's code. It built Hagia Sophia. It shaped Christian belief through its councils.

It also held the line against Persia and, for a time, brought back Roman rule in Italy and Africa. The state that emerged after Heraclius would last another eight centuries. Its full story is on the Eastern Roman Empire hub.

For the eastern empire after Rome, our guide to the best Roman history books picks The New Roman Empire. It covers Byzantium to 1453.

Verdict: the Roman Empire of the East

The Roman Empire of the East was the half of the Roman state ruled from Constantinople after 395. It survived the 400s when the West fell. It reached a new peak under Justinian I. In the 600s it lost its eastern provinces.

It became the Greek-speaking empire that historians call Byzantine. The events are well recorded. Only the choice of when to start calling it "Byzantine" is disputed. For the earlier united empire, see the Roman Empire page.

Sources checked for this page

• Britannica, "Byzantine Empire: The 6th century, from East Rome to Byzantium"
• Britannica, "Theodosius I"
• Britannica, "Justinian I"
• Britannica, "Heraclius"
• Oxford Academic, "The New Roman Empire: A History of Byzantium"
• World History Encyclopedia, "Byzantine Empire"

Questions people also ask

What was the Roman Empire of the East?

The eastern half of the Roman Empire, ruled from Constantinople after the empire was divided between the sons of Theodosius I in 395. It continued until the Ottoman conquest of 1453.

Who was the first emperor of the Eastern Roman Empire?

Arcadius, elder son of Theodosius I, is usually counted as the first emperor of the separate Eastern court, from 395. Some histories start instead with Constantine I, who founded Constantinople in 330.

Why did the Eastern Roman Empire survive when the West fell?

It was richer and more populous, its capital was protected by the sea and massive walls, and it could deal with Persia by treaty while paying off or redirecting invaders. Historians weigh these factors differently.

When did the Eastern Roman Empire become Byzantine?

There is no fixed date. Many historians mark the change in the 7th century, under Heraclius, when Greek replaced Latin in government and the empire lost its eastern and southern provinces.

What was the capital of the Eastern Roman Empire?

Constantinople, on the Bosporus, dedicated by Constantine I in 330 on the site of the Greek city of Byzantium. It is now Istanbul in Turkey.