Roman Empire

Roman Empire Senatus Populusque Romanus (Latin) Imperium Romanum[a] (Latin) Βασιλεία τῶν Ῥωμαίων (Ancient Greek) Basileía tôn Rhōmaíōn
27 BC–AD 395 (unified)[1] AD 395–476/480 (Western) AD 395–1453 (Eastern)
Vexillum with the imperial aquila Imperial aquila
Roman Empire in AD 117 at its greatest extent, at the time of Trajan's death   vassals[2][b]
Roman territorial evolution from the rise of the city-state of Rome to the fall of the Western Roman Empire
Capital	Rome (27 BC–AD 330)[c] Constantinople (330–1453)[d]
Official languages	Latin
Common languages	Regional languages
Religion	Imperial cult-driven polytheism (until AD 380; with henotheistic solar cult of Sol Invictus from 274–380) Nicene Christianity (officially from AD 380)
Demonym(s)	Roman
Government	Semi-elective absolute monarchy (de facto)
Emperor
• 27 BC – AD 14	Augustus
• 98–117	Trajan
• 138–161	Antoninus Pius
• 270–275	Aurelian
• 284–305	Diocletian
• 306–337	Constantine I
• 379–395	Theodosius I[e]
• 474–480	Julius Nepos
• 475–476	Romulus Augustus[f]
• 527–565	Justinian I
• 610–641	Heraclius
• 780–797	Constantine VI[g]
• 976–1025	Basil II
• 1143–1180	Manuel I
• 1449–1453	Constantine XI[h]
Historical era	Classical era to Late Middle Ages
• War of Actium	32–30 BC
• Empire established	30–2 BC
• Octavian named augustus	16 January 27 BC
• Constantinople becomes capital	11 May 330
• Final East-West divide	17 January 395
• Deposition of Romulus Augustus	4 September 476
• Murder of Julius Nepos	9 May 480
• Fourth Crusade	12 April 1204
• Reconquest of Constantinople	25 July 1261
• Fall of Constantinople	29 May 1453
• Fall of Trebizond	15 August 1461
Area
25 BC[15]	2,750,000 km2 (1,060,000 sq mi)
AD 117[15][16]	5,000,000 km2 (1,900,000 sq mi)
AD 390[15]	3,400,000 km2 (1,300,000 sq mi)
Population
• 25 BC[17]	56,800,000
Currency	Sestertius,[i] aureus, solidus, nomisma
Preceded by Succeeded by Roman Republic Western Roman Empire Eastern Roman Empire

The Roman Empire^[a] was the post-Republican period of ancient Rome. It included large territorial holdings around the Mediterranean in Europe, North Africa, and Western Asia, and was ruled by emperors. From the accession of Augustus as the first Roman emperor to the military anarchy of the 3rd century, it was a Principate with Italia as the metropole of its provinces and Rome as its sole capital. The Empire was later ruled by multiple emperors who shared control over the Western and Eastern Roman Empire. The imperial seat moved from Rome to Byzantium; following the collapse of the West in 476, it became its sole capital as Constantinople. The adoption of Christianity as the state church in 380 and the fall of the Western Roman Empire conventionally marks the end of classical antiquity and the beginning of the Middle Ages.

The predecessor state of the Roman Empire, the Roman Republic, became severely destabilized in civil wars and political conflicts, eventually culminating in the victory of Octavian over Mark Antony and Cleopatra at the Battle of Actium in 31 BC and the subsequent conquest of the Ptolemaic Kingdom in Egypt. The Roman Senate granted Octavian overarching power (imperium) and the new title of Augustus, making him the first Roman emperor. The vast Roman territories were organized in senatorial and imperial provinces except Italy, which continued to serve as a metropole.

The first two centuries of the Roman Empire saw a period of unprecedented stability and prosperity known as the Pax Romana (lit. 'Roman Peace'). Rome reached its greatest territorial expanse during the reign of Trajan (AD 98–117); a period of increasing trouble and decline began with the reign of Commodus (177–192). In the 3rd century, the Empire underwent a crisis that threatened its existence, as the Gallic and Palmyrene Empires broke away from the Roman state, and a series of short-lived emperors led the Empire. It was reunified under Aurelian (r. 270–275). To stabilize it, Diocletian set up two different imperial courts in the Greek East and Latin West in 286; Christians rose to positions of power in the 4th century following the Edict of Milan of 313. Shortly after, the Migration Period, involving large invasions by Germanic peoples and by the Huns of Attila, led to the decline of the Western Roman Empire. With the fall of Ravenna to the Germanic Herulians and the deposition of Romulus Augustus in AD 476 by Odoacer, the Western Roman Empire finally collapsed; the Eastern Roman emperor Zeno formally abolished it in AD 480. The Eastern Roman Empire survived for another millennium, until the fall of Constantinople in 1453.^[j]

Due to the Roman Empire's vast extent and long endurance, the institutions and culture of Rome had a lasting influence on the development of language, religion, art, architecture, literature, philosophy, law, and forms of government in the territory it governed. Latin evolved into the Romance languages, while Medieval Greek became the language of the Eastern Roman Empire. The Empire's adoption of Christianity led to the formation of medieval Christendom. Roman and Greek art had a profound impact on the Italian Renaissance. Rome's architectural tradition served as the basis for Romanesque, Renaissance and Neoclassical architecture, and also influenced Islamic architecture. The rediscovery of Greek and Roman science and technology (which also formed the basis for Islamic science) in medieval Europe led to the Scientific Renaissance and Scientific Revolution. The corpus of Roman law has its descendants in many modern legal systems, such as the Napoleonic Code, while Rome's republican institutions have left an enduring legacy, influencing the Italian city-state republics of the medieval period, as well as the early United States and other modern democratic republics.

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