Auxilia
The auxilia (Latin: [au̯kˈs̠ɪlia]; lit. 'auxiliaries') were introduced as non-citizen troops attached to the citizen legions by Augustus after his reorganisation of the Imperial Roman army from 27 BC.[1] By the 2nd century, the Auxilia contained the same number of infantry as the legions and, in addition, provided almost all of the Roman army's cavalry (especially light cavalry and archers) and more specialised troops. The auxilia thus represented three-fifths of Rome's regular land forces at that time. Like their legionary counterparts, auxiliary recruits were mostly volunteers, not conscripts.
See also: List of Roman auxiliary regiments
The Auxilia were mainly recruited from the peregrini, free provincial subjects who did not hold Roman citizenship and constituted the vast majority of the population in the 1st and 2nd centuries (c. 90% in the early 1st century). In contrast to the legions, which only admitted Roman citizens, members of the Auxilia could be recruited from territories outside of Roman control.
Reliance on the various contingents of non-Italic troops, especially cavalry, increased when the Roman Republic employed them in increasing numbers to support its legions after 200 BC. The Julio-Claudian period (27 BC–68 AD) saw the transformation of the Auxilia from motley levies to a standing corps with standardised structure, equipment and conditions of service. By the end of the period, there were no significant differences between legionaries and auxiliaries in terms of training and combat capability.
Auxiliary regiments were often stationed in provinces other than that in which they were originally raised, for reasons of security and to foster the process of Romanization in the provinces. The regimental names of many auxiliary units persisted into the 4th century, but by then the units in question were different in size, structure, and quality from their predecessors.
Unit types and structure[edit]
Regular unit types[edit]
The following table sets out the official, or establishment, strength of auxiliary units in the 2nd century. The real strength of a unit would fluctuate continually, but would likely have been somewhat less than the establishment most of the time.
Irregular allied forces[edit]
Throughout the Principate period, there is evidence of ethnic units of barbari outside the normal auxilia organisation fighting alongside Roman troops. To an extent, these units were simply a continuation of the old client-king levies of the late Republic: ad hoc bodies of troops supplied by Rome's puppet petty-kings on the imperial borders for particular campaigns. Some clearly remained in Roman service beyond the campaigns, keeping their own native leadership, attire and equipment and structure. These units were known to the Romans as socii ('allies'), symmachiarii (from symmachoi, Greek for 'allies') or foederati ('treaty troops' from foedus, 'treaty'). One estimate puts the number of foederati in the time of Trajan at about 11,000, divided into about 40 numeri (units) of about 300 men each. The purpose of employing foederati units was to use their specialist fighting skills.[134] Many of these would have been troops of Numidian cavalry (see light cavalry above).
The foederati make their first official appearance on Trajan's Column, where they are portrayed in a standardised manner, with long hair and beards, barefoot, stripped to the waist, wearing long trousers held up by wide belts and wielding clubs. In reality, several different tribes supported the Romans in the Dacian wars. Their attire and weapons would have varied widely. The Column stereotypes them with the appearance of a single tribe, probably the most outlandish-looking, to differentiate them clearly from the regular auxilia.[135] Judging by the frequency of their appearance in the Column's battle scenes, the foederati were important contributors to the Roman operations in Dacia. Another example of foederati are the 5,500 captured Sarmatian cavalrymen sent by Emperor Marcus Aurelius (r. 161–180) to garrison a fort on Hadrian's Wall after their defeat in the Marcomannic Wars.[136]
Names, titles and decorations[edit]
Regimental names[edit]
The nomenclature of the great majority of regiments followed a standard configuration: unit type, followed by serial number, followed by name of the peregrini tribe (or nation) from whom the regiment was originally raised, in the genitive plural case e.g. cohors III Batavorum ('3rd Cohort of Batavi'); cohors I Brittonum ('1st Cohort of Britons'). Some regiments combine the names of two peregrini tribes, most likely after the merger of two previously separate regiments e.g. ala I Pannoniorum et Gallorum ('1st Wing of Pannonii and Gauls'). A minority of regiments are named after an individual, mostly after the first prefect of the regiment, e.g. ala Sulpicia (presumably named after a prefect whose middle (gens) name was Sulpicius). The latter is also an example of a regiment that did not have a serial number.[170]
Titles[edit]
Regiments were often rewarded for meritorious service by the grant of an honorific title. The most sought-after was the prestigious c.R. (civium Romanorum 'of Roman citizens') title. In the latter case, all the regiment's members at the time, but not their successors, would be granted Roman citizenship. But the regiment would retain the c.R. title in perpetuity. Another common title was the gens name of the emperor making the award (or founding the regiment) e.g. Ulpia: the gens name of Trajan (Marcus Ulpius Traianus r.98–117). Other titles were similar to those given to the legions e.g. pia fidelis (p.f. 'dutiful and loyal').[171]
Decorations[edit]
The Roman army awarded a variety of individual decorations (dona) for valour to its legionaries. Hasta pura was a miniature spear; phalerae were large medal-like bronze or silver discs worn on the cuirass; armillae were bracelets worn on the wrist; and torques were worn round the neck, or on the cuirass. The highest awards were the coronae ('crowns'), of which the most prestigious was the corona civica, a crown made of oak leaves awarded for saving the life of a Roman citizen in battle. The most valuable award was the corona muralis, a crown made of gold awarded to the first man to scale an enemy rampart. This was awarded rarely, as such a man hardly ever survived.[159]
There is no evidence that auxiliary common soldiers received individual decorations, although auxiliary officers did. Instead, the whole regiment was honoured by a title reflecting the type of award e.g. torquata (awarded a torque) or armillata (awarded bracelets). Some regiments would, in the course of time, accumulate a long list of titles and decorations e.g. cohors I Brittonum Ulpia torquata pia fidelis c.R..[171]