Roman Empire OOB
Legio I
Germanica
Legio II
Sabina
Legio III
Cyrenaica
-Legio III
Gallica
Legio IV
Macedonia
-Legio IV
Scythica
Legio V
Alaudae
Legio VI
Ferrata
Legio VI
Gemina
-Legio VI
Victrix
Legio VII
Paterna
Legio VIII
Augusta
Legio IX
Triumphalis
-Legio IX
Hispana
Legio X
Equestris
-Legio X
Gemina
Legio XI
Legio XII
Victrix
-Legio XII
Antiqua
-Legio XII
Fulminata
Legio XIII
Gemina
Legio XVIII
Libyca
Legio XXX
Classica
Early Empire legions
Legio I
Legio I Germanica (German) - 48 BC to 70 (Batavian rebellion), Julius Caesar
Legio I Adiutrix (Helper) - 68 to (at least) 444, Nero
Legio I Italica (Italian) - September 22, 66 to (at least) 5th century, established at Misenum, Nero
Legio I Macriana liberatrix (liberator of Macer) - 68 to 69, Lucius Clodius Macer, governor of Africa
Legio I Minervia (protected by goddess Minerva) - 82 to (at least) 4th century, Domitian
Legio I Parthica (Parthian) - 197 to early 6th century, Septimius Severus
Legio II
Legio II Adiutrix Pia Fidelis (helper faithful and loyal) - 70 to (at least) 3rd century, Vespasian
Legio II Augusta (levied by Augustus) - before 9 to at least 3rd century (emblem: capricorn, pegasus).
Legio II Gallica (from Gallia) - established Arausio, modern Orange, France, possibly another cognomen for the Legio II Augusta
Legio II Italica (Italian) - 165 to beginning of the 5th century, Marcus Aurelius
Legio II Parthica (Parthian) – 197 until, at least half of 4th century, Lucius Septimius Severus
Legio II Traiana Fortis (Trajan strong legion) - 105 to (at least) 5th century, Trajan
Legio II Germanica (German) - new cognomen from 3rd century, Caracalla
Legio III
Legio III Augusta (levied by Augustus) – 43 BC to (at least) late 4th century, Augustus (emblem: pegasus)
Legio III Cyrenaica (from Cyrenaica) – probably around 36 BC to (at least) 5th century, Mark Antony
Legio III Gallica (from Gallia) – around 49 BC to at least early 4th century, Julius Caesar (emblem: bull)
Legio III Italica (Italian) - 165 to at least early 4th century, Marcus Aurelius
Legio III Parthica (Parthian) - around 197 to at least early 5th century, Lucius Septimius Severus
Legio IV
Legio IV Macedonica (Macedonian) - 48 BC to 70 (disbanded by Vespasian), Julius Caesar (emblem: bull, capricorn)
reconstituted under the name of Legio IV Flavia Felix (lucky Flavian legion) - about 70 to before 400, Vespasian
Legio IV Scythica (from Scythia) - around 42 BC to at least early 5th century, Mark Antony (emblem: capricorn)
Legio V
Legio V Alaudae (Larks) - 52 BC to 70 (destroyed in the Batavian rebellion), Julius Caesar (emblem: elephant)
Legio V Macedonica (Macedonian) - 43 BC to after 400, consul Gaius Vibius Pansa Caetronianus and Augustus (emblem: bull)
Legio V Urbana, probably early name of the Legio V Macedonica
Legio V Gallica, probably early name of the Legio V Macedonica
Legio VI
Legio VI Ferrata (Ironclad) - 52 BC to after 250, Julius Caesar (emblem: bull, wolf and Romulus and Remus)
Legio VI Victrix (Victorious) - 41 BC to late 4th century, Augustus (emblem: bull)
Legio VI Hispaniensis, another name of the Legio VI Victrix
Legio VII
Legio VII Claudia Pia Fidelis (faithful and loyal Claudian legion) - 58 BC to end of 4th century, Julius Caesar (emblem: bull)
Legio VII Paterna (Paternal), name of Legio VII Claudia Pia Fidelis up to 42
Legio VII Gemina (Twin) - October 68 to end of 4th century, Galba
Legio VIII
Legio VIII Augusta (raised by Augustus), 59 BC to after 371, Caesar Augustus
Legio VIII Gallica (from Gallia), early name of VIII Augusta
Legio VIII Mutinensis (from Mutina), early name of VIII Augusta
Legio IX
Legio IX Hispana (Spanish) - before 41 BC to before 160, Caesar Augustus
Legio X
Legio X Fretensis (Of the sea straits) - 41/40 BC to at least 260, Augustus (emblem: boar, bull, dolphin, galley)
Legio X Gemina (Twin) - 44 BC to early 5th century, Lepidus
Legio XI
Legio XI Claudia Pia Fidelis (faithful and loyal Claudian legion) - 42 BC to early 5th century, Caesar Augustus (emblem: Neptune)
Legio XII
Legio XII Fulminata (wielder of thunderbolt) - 43 BC to (at least) 5th century, Lepidus (emblem: thunderbolt)
Legio XIII
Legio XIII Gemina (Twin) - 41 BC to (at least) 5th century, Caesar Augustus
Legio XIV
Legio XIV Gemina Martia Victrix (Twin and Martial Victory) - Augustus
Legio XV
Legio XV Apollinaris (devoted to the god Apollo) - 41/40 BC to 5th century - Augustus
Legio XV Primigenia (devoted to goddess Fortuna) - 39 to 70 (destroyed in the Batavian rebellion), Caligula
Legio XVI
Legio XVI Gallica (from Gallia) - 41/40 BC to 70 (Batavian rebellion) - Augustus (emblem: lion)
Legio XVI Flavia Firma (standfast Flavian legion) reconstitution of the XVI Gallica - 70 to 4th century - Vespasian
Legio XVII
Legio XVII - 41 BC to 9 AD (Battle of the Teutoburg Forest), Augustus
Legio XVIII
Legio XVIII - 41 BC to 9 AD (Battle of the Teutoburg Forest), Augustus
Legio XIX
Legio XIX - 41 BC to 9 AD (Battle of the Teutoburg Forest), Augustus
Legio XX
Legio XX Valeria Victrix (Valorous and Victorious) - after 31 BC to late 3rd century, Augustus (emblem: boar)
Legio XXI
Legio XXI Rapax (Predator) - 31 BC to 92 (destroyed in Pannonia), Augustus (emblem: capricorn)
Legio XXII
Legio XXII Deiotariana (levied by Deiotarus) - 48 BC to about 132-136 (probably destroyed in rebellion in Iudaea), Deiotarus
Legio XXII Primigenia (devoted to goddess Fortuna) - 39 to 3rd century, Caligula
Legio XXX
Legio XXX Ulpia Victrix (Victorious Ulpian legion) - 105 to early 5th century, Trajan
Late Empire legions
Shield pattern of the palatina legion of the Ioviani seniores, according to Notitia Dignitatum.Diocletian reorganized the Roman army, in order to better handle the menace of the barbarians from north Europe as well as that of the Persians from the East. The army was formed by border and field units.
The border (limitanei) units were to occupy the limes, the structured border fortifications, and were formed by professional soldiers with an inferior training.
The field units were to stay well behind the border, and to move quickly where they were needed, with both offensive and defensive roles. Field units were formed by elite soldiers with high-level training and weapons. They were further divided into:
Scholae units – the personal guard of the Emperor, created to substitute the Praetorian Guard disbanded by Constantine I;
Palatinae units – "palace" units were the highest ranked units;
Comitatenses units – "line" or "regular" units, some of them were new legions, other were Early Empire legions;
Pseudocomitatenses units – they were limitanei units diverted into the field army and often kept there; some Early Empire legions became pseudocomitatenses units.
Some of these units kept a numbering scheme. Primary source is the Notitia Dignitatum
Legio I
I Armeniaca (from Armenia) – pseudocomitatensis under Magister militum per Orientis command, fought under Julian the Apostate against the Persians
I Flavia Constantia (reliable Flavian) – comitatensis unit under Magister militum per Orientis command
I Flavia Gallicana Constantia (reliable Flavian legion from Gallia) – pseudocomitatensis under Magister Peditum per Gallias command
I Flavia Martis (Flavian legion devoted to Mars) – pseudocomitatensis
I Flavia Pacis (Flavian legion of peace) – comitatensis under Magister Peditum
I Flavia Theodosiana – comitatensis
I Illyricorum (of the Illyrians) – stationed at Palmyra
I Iovia (devoted to Jupiter) – levied by Diocletian, stationed in Scythia Minor
I Isaura Sagitaria (archers from Isauria) – pseudocomitatensis under Magister militum per Orientis command
I Iulia Alpina – pseudocomitatensis under Magister Peditum command in Italia
I Martia
I Maximiana Thaebanorum (the Thebans of Maximianus) – comitatensis unit stationed near Thebes, Egypt, and probably fighting in the battle of Adrianople
I Noricorum (of the Noricans) – stationed in Noricum
I Pontica
Legio II
II Armeniaca – pseudocomitatensis
II Britannica – comitatensis under Magister Peditum
II Flavia Constantia – comitatensis under Magister Peditum
II Flavia Virtutis – comitatensis under Magister Peditum
II Herculia (devoted to Hercules) – levied by Diocletian, stationed in Scythia Minor
II Isaura
II Iulia Alpina – pseudocomitatensis under Magister Peditum, in Comes Illyricum command
II Felix Valentis Thebaeorum – comitatensis
Legio III
III Diocletiana
III Flavia Salutis – comitatensis under Magister Peditum
III Herculea – comitatensis under Magister Peditum, in Comes Illyricum command
III Isaura
III Iulia Alpina – comitatensis under Magister Peditum command in Italia
Legio IIII
IIII Italica
IIII Martia
IIII Parthica
Legio V
V Iovia (maybe the Jovians)
V Parthica
Legio VI
VI Gemella
VI Gallicana
VI Herculia (maybe the Herculians)
VI Hispana
VI Parthica
Legio XII
XII Victrix
References:
List of Roman Legions
Deployment of the Roman Legions