Legion: chronological

Legion: infantry unit in the Roman army.

Julius Caesar
Julius Caesar

Before Caesar:

Julius Caesar, 58 BCE

Caesar, 57 BCE:

Caesar, 53 BCE:

Caesar, 52 BCE:

Caesar, 49-48 BCE (using consular numbers):

Timeline of legions
Timeline of legions

Pansa, 43 BCE:

Mark Antony:

Portrait of Augustus as pontifex maximus
Portrait of Augustus as pontifex maximus

Octavian, 41-40 BCE:

Octavian 30 BCE:

Battle in Teutoburg Forest:

Caligula, 39 CE:

Nero
Nero

Nero, 66:

Nero, 68:

Galba, 68:

Vespasian, 70:

Domitian
Domitian

Domitian, 83:

War against Decebalus, 92:

Trajan, 105:

Uncertain date:

Marcus Aurelius, 168:

Septimius Severus
Septimius Severus

Septimius Severus, 197:

Heliogabalus, 220:

Severus Alexander, 230?

Gordian III, 238?:

Philip the Arab (244-249)?

Valerian, 253:

Laelianus (268-269)?

The following units are known from late-ancient sources and are called "legions". In fact, however, they were no longer the elite troops of the Roman empire. The main forces were cavalry units; the legions were the garrisons of the frontier zone.

Probus
Probus

Aurelian (270-275):

Probus (276-282)

Before Diocletian:

Diocletian
Diocletian

Diocletian (284-305):

Constantius I Chlorus (293-306):

Constans

Constantius II (337-361)

Constans (337-350):