A Brief History
Legio XIV Gemina Martia Victrix was levied by Octavian after 41 BC. The cognomen Gemina (twin, in Latin) suggests that the legion resulted from fusion of two previous ones, one of them possibly being the XIVth that fought in the Battle of Alesia. Martia Victrix (martial victory) were cognomens added by Nero following the victory over Queen Boudicca. The emblem of the legion was the Capricorn and the Black Eagle.
Stationed in Moguntiacum, Germania Superior, since, 9, XIV Gemina Martia Victrix was one of four legions used by Aulus Plautius and Claudius in the Roman invasion of Britain in 43, and took part in the defeat of Queen Boudicca in 60 or 61. In 68 it was stationed in Gallia Narbonensis.
In 89 the governor of Germania Superior, Lucius Antonius Saturninus, rebelled against Domitian, with the support of the XIVth and of the XXI Rapax, but the revolt was suppressed.
When the XXIst was lost, in 92, XIV Gemina was sent to Pannonia to replace it, camping in Vindobona. After a war with the Sarmatians and Trajan's Dacian Wars (101-106), the legion was moved to Carnuntum, where it stayed for three centuries. Some subunits of the XIVth fought in the wars against the Mauri, under Antoninus Pius, and the legion participated in the Parthian campaign of Emperor Lucius Verus. During his war against the Marcomanni, Emperor Marcus Aurelius based his headquarters in Carnuntum.
In 193, after the death of Pertinax, the commander of the XIVth, Septimius Severus, was acclaimed emperor by the Pannonian legions, and above all by his own. The XIV Gemina fought for its emperor in his march to Rome to attack usurper Didius Julianus (193), contributed to the defeat of the usurper Pescennius Niger (194), and probably fought in the Parthian campaign that ended with the sack of the capital of the empire, Ctesiphon (198).
In the turmoil following the defeat of Valerian, XIV Gemina supported usurper Regalianus against Emperor Gallienus (260), then Gallienus against Postumus of the Gallic empire (earning the title VI Pia VI Fidelis ("six times faithful, six times loyal"), and, after Gallienus death, Gallic Emperor Victorinus (269-271).
At the beginning of the 5th century, XIV Gemina still stayed at Carnuntum. It probably dissolved with the collapse of the Danube frontier in the 430s, although the Notitia Dignitatum lists a 'Quartodecimani Comitatensis' unit under the Magister Militum per Thracias; it is possible that this unit was XIV Gemina, and that it moved east to the surviving Empire after the fall of the West.