- Glossary definition: Roman Empire
Roman Empire

The area of the Old World conquered and controlled during the period of Roman history from 27 B.C.E., when Octavian took the power of what was effectively a constitutional monarch with the title of Augustus, until the barbarian invasions of the 4th-5th centuries, which followed the death of Constantine and ended with the overthrow of the last Roman emperor, Romulus Augustulus, in 476 A.D.