Roman Empire glossary: 48 terms explained
Plain-English definitions of the words used about the Roman Empire: its periods, government, provinces and army, and how its borders are mapped. Every term with a page of its own shows what it means on the map and uses real figures from the map data.
39 of the 48 terms have a page of their own. The rest are defined here, with a link to the page that covers them where there is one.
Periods and events
- Byzantine Empiremap pageThe Byzantine Empire is the name historians give to the Eastern Roman Empire in its later centuries, ruled from Constantinople until the Ottoman conquest in AD 1453.
- Crisis of the Third CenturyThe Crisis of the Third Century was a period of about fifty years, usually dated AD 235 to 284, when the Roman Empire nearly broke apart.
- DominateThe Dominate is the name historians give to the later Roman Empire, from about AD 284 under Diocletian.
- Eastern Roman EmpireThe Eastern Roman Empire was the eastern half of the Roman world after AD 395, ruled from Constantinople.
- Fall of Constantinoplemap pageThe fall of Constantinople was the capture of the Eastern Roman capital by the Ottoman Turks under Sultan Mehmed II on 29 May 1453.
- Fall of the Western Roman Empiremap pageThe fall of the Western Roman Empire is the end of imperial rule in the West, traditionally dated to AD 476, when the Germanic general Odoacer removed the last Western emperor, Romulus Augustulus.
- FoederatiFoederati were peoples or cities bound to Rome by a treaty, called a foedus.
- Gallic EmpireThe Gallic Empire is the modern name for a breakaway state that held Gaul, Britain and for a time Spain from about AD 260 to 274.
- Holy Roman Empire vs Roman EmpireNo.
- Migration PeriodThe Migration Period was the era, traditionally dated from about AD 375 to 568, when Goths, Vandals, Huns and other peoples moved into and across Europe, including the Western Roman Empire.
- Palmyrene EmpireThe Palmyrene Empire was a breakaway state in the Roman East, centred on the desert city of Palmyra in Syria and ruled by Queen Zenobia for her son.
- Pax RomanaThe Pax Romana, Latin for "Roman peace", is the long stretch of relative stability across the empire that began under Augustus.
- PrincipateThe Principate is the name historians give to the first period of the Roman Empire, from Augustus in 27 BC to about AD 284.
- Roman Empire at its heightmap pageThe Roman Empire reached its greatest extent in AD 117, at the death of Trajan, after his conquests in the east.
- Roman Empire vs Roman RepublicThe Roman Republic was ruled by elected officials and the Senate, and the Roman Empire by an emperor.
- Roman KingdomThe Roman Kingdom was the first period of Roman history, when Rome was ruled by kings.
- Roman RepublicThe Roman Republic was the period when Rome had no king and no emperor, and was run by elected officials and the Senate.
- Sack of Rome (410)The sack of Rome in AD 410 was the plundering of the city by the Visigoths under Alaric, who looted it for three days.
- TetrarchyThe Tetrarchy was the system of rule by four emperors that Diocletian set up in AD 293.
- Western Roman EmpireThe Western Roman Empire was the western half of the Roman world after the permanent split of AD 395, ruled from Milan and then Ravenna in Italy.
- Why did the Roman Empire splitmap pageThe Roman Empire split permanently in AD 395, when Theodosius I died and left the East and West to his two sons.
Government and provinces
- Client kingdomA client kingdom was a state that kept its own king but answered to Rome.
- ConsulA consul was one of the two senior magistrates of the Roman Republic, elected together each year.
- DioceseA Roman diocese was a group of provinces created in the late third century, probably by Diocletian.
- Imperial vs senatorial provinceUnder Augustus, Roman provinces were split into two groups.
- Limes (frontier)The limes (LEE-mayz) was the frontier of the Roman Empire.
- Praetorian prefectureA praetorian prefecture was the largest civil region of the late Roman Empire.
- Provincial governorA provincial governor was the Roman official sent to run a province.
- Roman citizenshipRoman citizenship was a privileged legal and political status for free people, giving rights to vote, own property, marry lawfully and get a fair trial.
- Roman emperorA Roman emperor was the sole ruler of the Roman state.
- Roman provinceA Roman province was a region outside Italy that Rome controlled and ruled through a governor.
- Roman SenateThe Roman Senate was the council of senior Romans that guided the state, first under the kings, then through the Republic and into the empire.
- SPQRSPQR stands for Senatus Populusque Romanus, Latin for "the Senate and People of Rome".
Places, army and people
- AuxiliaThe auxilia were the non-citizen units of the Roman army, recruited mostly from the provinces. They served beside the legions as infantry and cavalry, and a soldier who was honourably discharged could gain Roman citizenship.
- CivitasIn the Roman provinces a civitas was a self-governing community, usually a native tribe or city with its capital town.
- ColoniaA colonia was a Roman town founded or re-founded as a settlement of Roman citizens, often retired soldiers.
- Hadrian's Wallmap pageHadrian's Wall was a stone and turf frontier barrier built across northern Britain under the emperor Hadrian.
- Latin West and Greek EastThe Latin West and Greek East are the two cultural halves of the Roman Empire.
- Legionary fortressA legionary fortress was a large permanent base where a Roman legion lived, trained and was supplied.
- Mare NostrumMare Nostrum is Latin for Our Sea, the Roman name for the Mediterranean.
- MunicipiumA municipium was a Roman town that ran its own affairs under a charter while owing duties to Rome.
- Roman Britainmap pageRoman Britain was the Roman province of Britannia, covering most of England and Wales and, for periods, part of southern Scotland.
- Roman legionA Roman legion was the main fighting unit of the Roman army, made up of about 5,000 heavy infantry who were Roman citizens.
- RomanisationRomanisation is the name historians give to the spread of Roman language, law, towns and customs among the peoples Rome ruled.
Dates and the data
- BC and AD vs BCE and CEBC and AD and BCE and CE are two labels for exactly the same years.
- How big was the Roman Empiremap pageAt its greatest extent, in AD 117 under Trajan, the Roman Empire covered about 4.88 million square kilometres on our map.
- How historians map ancient bordersHistorians map ancient borders by piecing together written sources, inscriptions, milestones and archaeology, then drawing a best estimate.
- Pleiades gazetteerPleiades is a community-built gazetteer of ancient places, with locations, names and sources for towns, forts, ports and sites across the ancient world.