The origins of the legion are unclear, but it is first attested as part of Mark Antony's forces during the period of the Second Triumvirate (43-33 BC).

Cyrenaica was under the control of Marcus Aemilius Lepidus before 36 BC and of Mark Antony after that date; either of them might have established the Legio III.

[1] Pollard and Berry suggest that the legion was established by Lucius Pinarius Scarpus, an ally of Mark Antony who was his governor of Cyrenaica in the 30s BC.

[1] In 24 BC a Roman governor named Gaius Petronius took the legions, one of which was III Cyrenaica, and marched upstream along the Nile and reached Napata, the capital of Nubia.

[1] It is possible that one of them was sent to Tongeren in Gallia Belgica during the reign of Caligula, which may have been part of the army he wanted to use to invade Britain in 40 AD.

[1] In 175 AD, the legion sided with Avidius Cassius, a Roman general who revolted against Marcus Aurelius, but was killed by his own officers.

[1] During the civil war following the death of the emperor Commodus in 192 AD the Legio III Cyrenaica sided with the eastern pretender Pescennius Niger.

[1] The following is a list of campaigns and actions thought to have been seen by Legion III Cyrenaica during much of its existence: Osprey books: