A legion was around 5,000 heavily armed and armoured men who were, by the 2nd century AD, even more of an anachronism than the rams that still adorned the prow of every Roman warship in their fleets. Organised into ten cohorts, each of around 480 men, they were extremely effective in open battle, especially when complemented by their attached auxiliaries. Legionaries (never, please, ‘legionnaires’) were nevertheless unsuitable for garrisoning a province and all-too-easily wrong-footed by even the most basic of insurgencies (as all technologically dependent armies tend to be).
Britannia was to turn out to be a troubled (and troubling) place. It needed four legions until the end of the AD 80s and right up until the beginning of the 2nd century AD it still had three (II Augusta, IX Hispana, and XX Valeria Victrix). Then something happened, and at some point between AD 108 and 122 it was probably reduced to two, which was evidently not enough. So it came to pass that, (probably at the same time) in AD 122, three things were crated up and shipped in from Germania Inferior: 1. an emperor (the supreme commander of all Roman armies); 2. a new army commander (who also happened to be a chum of said supreme commander); and 3. a shiny new legion (VI Victrix). All three left their mark, but let’s first look at those three legions.
Legio II Augusta
Based at Caerleon-Isca since c.AD 75, the Second Augusta was a primary legion of the Exercitus Britannicus: it had arrived from Germania (that part later called Superior) in AD 43 and had made the province its home ever since. If there was a stain on its record, it was when its praefectus castrorum refused to support his army commander against the Boudican rebels. Its totemic animals, an important part of its corporate identity, were the capricorn and the winged horse, Pegasus.
Legio XX Valeria Victrix
Established in its fortress at Chester-Deva since c.AD 89, the Twentieth Valeria Victrix was likewise a primary British legion and came from what was to be Lower Germany (Neuss, to be precise). It may have been the intended garrison for the new Flavian legionary base at Inchtuthil, abandoned before it was finished, in which case it would have become the northernmost legion in the Empire. The Twentieth had their own dirty linen: in AD 68, their legate, Roscius Coelius, had rebelled against the commander of the Exercitus Britannicus, Trebellius Maximus, and incited the rest of the provincial army to join him, forcing Maximus to flee. The Twentieth took as its symbol the boar.
Legio VI Victrix
The newcomer. It seems to have arrived on the Tyne directly from its base at Xanten-Vetera in Germania Inferior, if the two altars discovered in the river near the likely site of the Pons Aelius are any indication. Those altars seem to show a legion very glad to be disembarked. We know both its outgoing (Propinquus) and incoming (P. Tullius Varro) commanders from AD 122 and we also know its tribunus laticlavius (second-in-command of a legion), the splendidly named M. Pontius Laelianus Larcius Sabinus. The Sixth Victrix was much less free and easy with its totemic animal on sculpture and inscriptions, but for what it’s worth it is thought to have been a bull.
As has been discussed, none of the legions building the Wall described themselves as a detachment or vexillatio, but there may well have been a vexillation present. An inscription records 3,000 troops from VII Gemina from Hispania Tarraconensis and VIII Augusta and XXII Primigenia from Germania Superior being sent on a Hadrianic expeditio Britannica. Were these extra troops to help with the construction process, or perhaps a draft of troops to bolster depleted British legions?
Auxiliaries and the fleet
An enterprise of this scale tended to suck in all who were available. Adding the forts and the Vallum to the original scheme of the Wall was obviously going to cause problems if the legions had to build those as well, so auxiliary units were drafted in to work on the Vallum and even the fleet (the classis Britannica) had a crack at building Benwell fort. Was that their reward for bringing over legio VI Victrix from Lower Germany?
During construction, the legions were preeminent. However, when the time came to man the Wall, the auxiliaries were to take a prominent, but by no means exclusive, role.
NEXT: The garrison