Roman-era

Roman Empire
Imperium Romanum  (Latin) Senatus Populusque Romanus (SPQR) Roman Senate and People Βασιλεία Ῥωμαίων (Ancient Greek) Basileía Rhōmaíōn
27  BC  – 395  AD 395 – 480 (Western) 395 – 1453 (Eastern) 1204 – 1461 (Trebizond)
Vexilloid Aureus of Augustus
The Roman Empire in 117 AD, at its greatest extent at the time of Trajan's death (its vassals in pink).
Capital		Rome (27 BC – AD 410) Mediolanum (286–402, Western) Augusta Treverorum Sirmium Ravenna (402–476, Western) Nicomedia (286–330, Eastern) Constantinople (330–1453, Eastern) Syracuse (663–669, Eastern)
Languages		Latin (official until 610) Greek (official after 610) Regional / local languages
Religion		Before AD 380: Imperial cult-driven polytheism From AD 380: Christianity
Government		Mixed, functionally absolute monarchy
Emperor
•	27  BC  – AD 14	Augustus (first)
•	98–117	Trajan
•	284–305	Diocletian
•	306–337	Constantine I
•	379–395	Theodosius I
•	474–480	Julius Nepos
•	527–565	Justinian I
•	976–1025	Basil II
•	1449–1453	Constantine XI
Legislature		Senate
Historical era		Classical era to Late Middle Ages
•	Final War of the Roman Republic	32–30 BC
•	Empire established	30–2 BC
•	Constantinople becomes capital	330
•	Final East West divide	395
•	Fall of the Western Roman Empire	476
•	Fourth Crusade	1202–1204
•	Reconquest of Constantinople	1261
•	Fall of Constantinople	29 May 1453
Area
•	25 BC	2,750,000 km² (1,061,781 sq mi)
•	AD 117	5,000,000 km² (1,930,511 sq mi)
•	AD 390	4,400,000 km² (1,698,849 sq mi)
Population
•	25 BC est.	56,800,000
Density		20.7 /km²  (53.5 /sq mi)
Currency		Sestertius,Aureus, Solidus, Nomisma
Preceded by Succeeded by Roman Republic Western Roman Empire Eastern Roman Empire

Mediolanum (286–402, Western)
Augusta Treverorum
Sirmium
Ravenna (402–476, Western)
Nicomedia (286–330, Eastern)
Constantinople (330–1453, Eastern)
Syracuse (663–669, Eastern)

The Roman Empire (Latin: Imperium Rōmānum; Classical Latin: [ɪmˈpɛ.ri.ũː roːˈmaː.nũː] Koine and Medieval Greek: Βασιλεία τῶν Ῥωμαίων, tr. Basileia tōn Rhōmaiōn) was the post-Roman Republic period of the ancient Roman civilization, characterized by government headed by emperors and large territorial holdings around the Mediterranean Sea in Europe, Africa and Asia. The city of Rome was the largest city in the world c. 100 BC – c. 400 AD, with Constantinople (New Rome) becoming the largest around 500 AD, and the Empire's populace grew to an estimated 50 to 90 million inhabitants (roughly 20% of the world's population at the time). The 500-year-old republic which preceded it was severely destabilized in a series of civil wars and political conflict, during which Julius Caesar was appointed as perpetual dictator and then assassinated in 44 BC. Civil wars and executions continued, culminating in the victory of Octavian, Caesar's adopted son, over Mark Antony and Cleopatra at the Battle of Actium in 31 BC and the annexation of Egypt. Octavian's power was then unassailable and in 27 BC the Roman Senate formally granted him overarching power and the new title Augustus, effectively marking the end of the Roman Republic.