The Roman Empire was one of the largest and most enduring states of the ancient world. At its height, it stretched from Britain and Spain in the west to Syria and Egypt in the east, spanning Europe, Asia and Africa — an empire across three continents. This chapter examines the workings of the Roman state from 27 BCE, when Octavian became the first emperor with the title Augustus, through the following three centuries that historians call the Principate.
The Roman Empire is studied not only for its conquests but for how it was administered and organised. A small ruling class based in the city of Rome governed an enormous and diverse population through a network of provincial governors, army legions, roads and taxes. The empire created the conditions for a shared Mediterranean economy and culture, yet it also rested on deep social inequalities, above all on slavery.
The chapter also follows the transformation of the Roman world in the third century CE, when the empire faced political crisis, economic strain and the spread of Christianity. The changes of this period — the rise of a new capital at Constantinople, the growing authority of the Church and the weakening of the old aristocracy — prepare the ground for the medieval world. The Roman Empire thus connects the classical and medieval phases of history across three continents.
The early empire was founded on the victory of Octavian, adopted heir of Julius Caesar, over his rivals. In 27 BCE the Senate gave Octavian the title Augustus ("the revered one"), and he is conventionally regarded as the first Roman emperor. The period that followed, until the crisis of the third century, is known as the Principate, because the emperors styled themselves princeps — "first citizen" — pretending to preserve the old republic.
Augustus brought peace after decades of civil war. The stability that followed, called the Pax Romana, allowed trade, law and urban life to flourish across the Mediterranean. The empire was surrounded by a network of military frontiers: in the north, the Rhine and Danube rivers marked the limit of Roman control, while in the east the empire faced its great rival, the Parthian (and later Sassanian Persian) kingdom.
Administration relied on a compact government. There were two main types of provinces: imperial provinces, governed by officials appointed directly by the emperor and holding legions, and senatorial provinces, administered by governors nominated by the Senate. Rome itself was governed by a prefect appointed by the emperor. The emperor's personal authority grew steadily, even though republican institutions such as the Senate continued to exist in name.
Agriculture dominated the Roman economy. Grain, wine, olive oil and vegetables were produced on farms large and small. Alongside peasant smallholders stood the latifundia — great estates worked by slaves and producing cash crops for the market. Italy and later the provinces supplied the cities, and the city of Rome itself depended on grain shipped from Egypt and North Africa.
Trade linked the whole empire. Romans imported silk from China, spices from India, incense from Arabia and slaves from beyond the frontiers. A standardised currency, the denarius, facilitated exchange, while a network of paved roads and safe sea routes moved goods and soldiers. Merchant guilds, markets and ports such as Ostia near Rome and Alexandria in Egypt were busy centres of commerce.
Roman society was sharply hierarchical. A tiny aristocracy of wealthy landowners dominated politics; below them were the equestrian order (knights/businessmen), then the mass of the common people, and at the bottom the slaves. Slaves performed all kinds of work — in fields, mines, workshops and households — and the institution of slavery was crucial to the economy. Freed slaves could become citizens and sometimes prosper as traders and craftsmen.
The Roman state was tolerant of the many religions of its subjects so long as they honoured the state gods and the emperor. Traditional Roman religion, Greek philosophy and mystery cults coexisted. Jewish communities existed throughout the empire, and from about the first century CE a new faith, Christianity, began to spread among Jews and gentiles.
Christianity grew from a small sect into a powerful movement. It offered salvation to all, including slaves and women, and its communities were tightly organised under bishops. The Roman authorities were initially suspicious; Christians were persecuted at intervals because they refused to worship the emperor. Yet Christianity continued to expand, and in 313 CE the emperor Constantine issued the Edict of Milan, granting toleration to Christians. In 380 CE Christianity was declared the official religion of the empire.
Latin and Greek were the languages of the empire — Latin in the west, Greek in the east. Roman law, architecture, engineering and literature had a lasting influence. Aqueducts, roads, amphitheatres and baths testify to Roman skills in engineering, while Roman law influenced European legal systems for centuries.
By the third century CE the empire faced a deep crisis. Emperors were overthrown by armies in rapid succession; frontiers came under pressure from Germanic peoples and from the revived Persian (Sasanian) empire; and inflation and plague weakened the economy and the population. The old political order of the Principate broke down.
The emperor Diocletian (r. 284-305 CE) responded by dividing the empire into eastern and western halves to make it easier to govern and defend. His reforms were consolidated by Constantine, who built a new capital at Constantinople on the site of the Greek city of Byzantium, in 330 CE. The eastern empire, with its capital at Constantinople, was wealthier and more urbanised, and it survived for another thousand years as the Byzantine Empire.
The later Roman empire also witnessed a transformation of society. The senatorial aristocracy lost political power while new elites — imperial officials, army officers and bishops — rose to prominence. Christianity reshaped culture and values. The western half of the empire, under pressure from Germanic invasions, disintegrated in the fifth century CE, but the eastern empire continued. The Roman legacy of law, religion, language and institutions profoundly shaped the development of Europe and the Mediterranean.
| Term | Meaning |
|---|---|
| Augustus | Title given to Octavian in 27 BCE, meaning 'the revered one' |
| Principate | The early empire, when emperors styled themselves princeps ('first citizen') |
| Pax Romana | Roman peace — the stability that followed the civil wars |
| Latifundia | Large estates worked by slaves producing cash crops |
| Denarius | Standard silver coin of the Roman empire |
| Edict of Milan | 313 CE order granting toleration to Christians |
| Date | Event |
|---|---|
| 27 BCE | Octavian becomes Augustus, first emperor |
| First to second centuries CE | Height of the Pax Romana |
| 284-305 CE | Reign of Diocletian; division of the empire |
| 313 CE | Edict of Milan; toleration of Christianity |
| 330 CE | Constantine founds Constantinople |
| Fifth century CE | Fall of the western Roman empire |
The Roman Empire was remarkable for its size, its stability and its enduring legacy. Spanning three continents, it united the Mediterranean world through roads, law, a common currency and a shared Graeco-Roman culture, while resting on the labour of slaves and the organisation of a centralised state. The crisis of the third century and the reforms of Diocletian and Constantine transformed the empire, relocating its centre of gravity to the east at Constantinople and admitting Christianity as the imperial religion. Although the western empire collapsed in the fifth century, Roman law, language, engineering and Christianity continued to shape Europe and the wider world for centuries, making this empire one of the foundational states of later history.