This is a list of Roman legions, including key facts about each legion, primarily focusing on the Principate (early Empire, 27 BC – 284 AD) legions, for which there exists substantial literary, epigraphic and archaeological evidence.
When Augustus became sole ruler in 31 BC, he disbanded about half of the over 50 legions then in existence. The remaining 28 legions became the core of the early Imperial army of the Principate (27 BC – AD 284), most lasting over three centuries. Augustus and his immediate successors transformed legions into permanent units, staffed by entirely career soldiers on standard 25-year terms.
During the Dominate period (near the end of the Empire, 284–476), legions were also professional, but are little understood due to scarcity of evidence compared to the Principate. What is clear is that late legions were radically different in size, structure, and tactical role from their predecessors, despite several retaining early period names. This was the result of the military reforms of Emperors Diocletian and Constantine I, and of further developments during the 4th century.
The legions were identified by Roman numerals, though the spelling sometimes differed from the modern standard. For example, in addition to the spellings "IV", "IX", "XIV", "XVIII" and "XIX", the respective spellings "IIII", "VIIII", "XIIII", "XIIX" and "XVIIII" were commonly used. Legions also bore a cognomen or nickname. Neither a legion's number or cognomen were likely unique enough to identify it, so the combination of the two is usually needed to identify a specific legion. For example, both Legio III Cyrenaica and Legio III Gallica were distinct, long-standing legions of the late Republic and Imperial periods. To visually identify legions, they also bore a specific emblem, a symbolic representation of the legion, frequently an animal or mythological figure, which appeared on the vexillum, a small rectangular flag that served as the legion's standard and carried both the emblem and name of the legion.
Late Republican legions
Republican legions were formed by compulsory levy of Roman citizens (who met a minimum property qualification) and raised whenever it was necessary. Usually they were authorized by the Roman Senate and later disbanded.
Throughout the late Republic, soldiers and commanders served only for short periods intending, respectively, to secure plunder or political advancement from military victory. There is little evidence of changes in the wealth and social backgrounds of the men who joined before and after the opening of recruitment; the pay remained pitiful. Conscription remained the main method by which Rome mustered troops. The evidence for the abolition of property requirements is very weak, The figures of 11,000, 4,000, and 1,500 are reported in the sources; "nothing warrants the presumption that the figures are to be arranged in a descending sequence" however. and there were no significant changes in population size or demographics that would drive such a reduction. The bulk of recruits were still landed citizens, who would appear poor to the elites authoring the surviving sources. Again, their pay was not enough to sustain professional career in the military, and soldiers generally did not expect land grants after discharge.
In the last century of the Republic, proconsuls governing frontier provinces became increasingly powerful. Their command of standing legions in distant and arduous military campaigns resulted in the allegiance of those units transferring from the Roman state to themselves. These imperatores (lit: victorious generals, from the title imperator they were hailed with by their troops) frequently fell out with each other and started civil wars to seize control of the state, such as Sulla, Caesar, Pompey, Crassus, Mark Antony and Octavian (later Augustus, the first Emperor himself). In this context, the imperatores raised many legions that were not authorised by the Senate, sometimes having to use their own resources. As civil wars were resolved, many of these "private" units would be disbanded, only for more to be raised to fight the next civil war. By the time Augustus emerged as sole ruler of Rome in 31 BC, over 50 legions were in existence, many of which were disbanded.
The legions included in the following list had a long enough history to be somehow remarkable. Most of them were levied by Julius Caesar and later included into Octavian's army, some of them were levied by Mark Antony.
Fimbrian legions: 86 BC – 66 BC, Lucius Valerius Flaccus. These two legions fought in the Mithridatic Wars. Legio I Germanica (Germanic): 48 BC – AD 70 (Revolt of the Batavi), Julius Caesar (emblem: bull) Legio II Sabina (Sabine): 43 BC – 4th century AD, early name of the Legio II Augusta, Octavian Legio III Cyrenaica (from Cyrene): probably to (at least) the 5th century, Mark Antony Legio III Gallica (Gallic): around 49 BC to at least early 4th century, Julius Caesar (emblem: bull) Legio IV Macedonica (Macedonian): 48 BC – AD 70 (renamed by Vespasian), Julius Caesar (emblem: bull, capricorn) Legio IV Scythica (from Scythia): to at least early 5th century, Mark Antony (emblem: capricorn) Legio V Macedonica (Macedonian): 43 BC – AD 637, Octavian (emblem: bull) Legio V Alaudae (Larks): 52 BC – AD 70 or 86 (destroyed either during the Batavian rebellion or by the Dacians in first Battle of Tapae), Julius Caesar (emblem: elephant) Legio VI Ferrata (Ironclad): 52 BC – after AD 250, Julius Caesar (emblem: bull, she-wolf and Romulus and Remus); twin legion of Legio VI Victrix Legio VI Victrix (Victorious): 41 BC – after AD 402, Octavian (emblem: bull) Legio VII Claudia Pia Fidelis (loyal and faithful to Claudius): before 58 BC – 44 BC, Julius Caesar; disbanded and re-formed by Octavian Legio VIII Augusta: 59 BC – 46 BC, Julius Caesar, originally named Gallica, disbanded and re-enlisted by Octavian as Legio VIII Augusta, 44 BC – AD 420 Legio IX Hispana (Hispanian): before 58 BC – AD 120-161 Legio X Equestris (Equestrian): before 58 BC – 45 BC, Julius Caesar's personal legion, later renamed as Legio X Gemina Legio X Fretensis (of the sea strait): levied by Octavian in 41/40 BC, recorded to have existed at least until the 410s Legio XI Claudia: 58 BC – 45 BC, Julius Caesar (emblem: Neptune), disbanded, reconstituted by Octavian Legio XII Fulminata (Thunderbolt): 57 BC – AD 45, Julius Caesar, first reconstituted by Lepidus in 43 BC, named by Mark Antony as Legio XII Antiqua (Ancient) Legio XIII Gemina (Twin): 57 BC – 45 BC: Julius Caesar, later (41 BC) reconstituted by Octavian. The legion that crossed the Rubicon with Caesar on his assault on Rome. Legio XIV Gemina Martia Victrix (Twin martial and victorious): 57 BC – 48 BC: Julius Caesar, destroyed and reconstituted in 53 BC. Reconstituted by Octavian after 41 BC. Legio XV Apollinaris (Apollo's) 41 BC – 40 BC, Octavian, raised to end the occupation of Sicily by Sextus Pompeius. Legio XVI Gallica (Gallic) 41 BC – 40 BC, Octavian, disbanded after Batavian revolt in AD 70. Legio XVII raised by Octavian in 41 BC, destroyed in Teutoburg forest in AD 9 with XVIII and XIX legions. Legio XVIII raised by Octavian in 41 BC, destroyed in Teutoburg forest in AD 9 with XVII and XIX legions Legio XIX raised by Octavian in 41 BC, destroyed in Teutoburg forest in AD 9 with XVII and XVIII legions Legio XX Valeria Victrix (Victorious Valeria) raised by Octavian in 31 BC. Legio XX Siciliana: 36 BC – 6 BC, Octavian probably for his campaign against Sextus Pompey. Legio XXI Rapax (Predator) raised by Octavian in 31 BC : 49 BC – 42 BC, Julius Caesar : 49 BC – 30 BC, Julius Caesar : 49 BC – 30 BC, Julius Caesar : 47 BC – 31 BC, Julius Caesar : 49 BC – 30 BC, Julius Caesar (Naval): 48 BC – 41 BC, Julius Caesar
Early Empire legions
Codes for Roman provinces in the table:
|AEG||Aegyptus||(Egypt) |- |AFR||Africa||(Tunisia/Western Libya) |- |AQ||Aquitania||(South-Western France) |- |AR||Arabia Petraea||(Jordan/Negev/Sinai) |- |BRIT||Britannia||(England/Wales) |- |CAP||Cappadocia||(Central/Eastern Turkey) |- |DC||Dacia||(Romania/Serbia) |- |DLM||Dalmatia||(Bosnia-Herzegovina/Croatia/Montenegro/Kosovo/Serbia) |- |GAL||Galatia||(Central Turkey) |- |GI||Germania Inferior||(Netherlands/Rhineland) |- |GS||Germania Superior||(Alsace-Lorraine/Rhineland) |- |HISP||Hispania Tarraconensis||(Central Spain) |- |IT||Italia||(Italy) |- |JUD||Judaea||(Israel/Palestine ) |- |MAUR||Mauretania||(Western Maghreb) |- |MCD||Macedonia||(Greece/Albania/North Macedonia/Bulgaria) |- |MI||Moesia Inferior||(Romania/Bulgaria) |- |MS||Moesia Superior||(Serbia) |- |NR||Noricum||(Austria) |- |PAN||Pannonia||(Hungary/Slovakia/Croatia/Slovenia) |- |RT||Raetia||(Switzerland/Germany) |- |SYR||Syria||(Syria/Lebanon)
+Roman legions of the early Empire (units founded between 59 BC and AD 250)Legion no.and title (cognomen)Mainlegionary baseEmblemDate founded/founderDatedisbandedCastra legionaria (legion bases)* = main base. Start date 31 BC if unspecifiedNotesI AdiutrixSzőny, HungaryCapricorn68 Nero44470–86 Moguntiacum (GS)86 – mid-5th century Brigetio* (PAN)"1st Rescuer"; received the cognomina Pia Fidelis Bis ("twice loyal and faithful") and Constans ("reliable") sometime in the 3rd century. Raised from marines of Classis Misenensis.I GermanicaBonn, GermanyBull Caesar70 DDto 16 BC HISP – AD 70 Bonna* (GI)Disbanded for cowardice in Batavi revoltI ItalicaSvishtov, BulgariaBoar66 Neropost 40070 – early 5th century Novae* (MI)Raised for aborted Caucasus warI Macriana Liberatrix68 Macer69 DD(Raised for mutiny against Nero by Macer, gov of AFR)liberatrix: "Liberator 1st". Disbanded by GalbaI MinerviaBonn, GermanyMinerva82 Domitianpost 30082 – 4th century Bonna* (GI)"Minerva-revering 1st"I ParthicaSinjar, IraqCentaur197 S. Severuspost 400197 – early 5th century Nisibis* (SYR)Raised for Severus' Parthian campaign in 197II AdiutrixBudapest, HungaryCapricorn70 Vespasianafter 26970–87 BRIT87–106 MS106 – at least 269 Aquincum* (PAN)"2nd Rescuer." Raised from marines of Classis RavennatisII AugustaCaerleon, WalesCapricorn Caesarafter 300to HISP43–74 BRIT74 – at least 255 Isca Augusta* (BRIT)Failed to engage Boudica AD 60. at Rutupiae (BRIT)II ItalicaEnns, AustriaShe-Wolf165 M. Aureliusafter 400180 – Lauriacum* (NR)Capitoline Wolf—Rome's national emblemII ParthicaCastra Albana, ItalyCentaur197 S. Severusafter 312197–218 Castra Albana (IT)218–234 Apamea (SYR)238 – Castra Albana(IT)4th century recorded at Bezabde (SYR)II TraianaAlexandria, EgyptHercules105 Trajanafter 400125 – 5th century Nicopolis* (AEG)Traiana secunda fortis: "Trajan's valliant 2nd"III AugustaBatna, AlgeriaPegasus Augustusafter 350to 20 AFR20–75 Ammaedara74 – after 350+ Lambaesis* (MAUR)Decimated for cowardice in Mauri war (AD 18)III CyrenaicaBusra, Syria M. Antonyafter 400to 35 Thebes35–125 Alexandria AEG125 – 5th century Bostra* AR"3rd from Cyrene"III GallicaRaphanea, SyriaTwo Bulls Caesarafter 30031 BC – 4th century Raphanea* (SYR)tertia Gallica: "3rd from Gaul"III ItalicaRegensburg, GermanyStork165 M. Aureliusafter 300165 – 4th century Castra Regina* (RT)Raised for war on MarcomanniIII ParthicaRas al-Ayn, SyriaBull197 S. Severusafter 400197 – 4th century Resaena* (SYR)Raised for Severus' Parthian campaign in 197IV Flavia FelixBelgrade, SerbiaLion70 Vespasianbefore 40086–108 Singidunum* MS108-118/9 Bersobis* DC118/9-4th century Singidunum* (MS)"Lucky Flavian 4th". Reformed IV MacedonIV Italica231