By the end of the 2nd century BC, the Roman army was the dominant military force in the Mediterranean; at its heart was the legionary soldier. Already, the Roman army had witnessed significant evolution over the past centuries – transforming from a hoplite-centred force to one focussed on the manipular system.
But as the 1st century BC beckoned, and the Roman Republic entered its final stages, the Roman legionaries would experience further changes. Especially to their armour.
Marian and Augustan reforms
The next major evolution of the legionary was under the reforms of the highly successful soldier and seven-time consul Gaius Marius at the beginning of the 1st century BC. He did away with the manipular system completely and rebuilt the legions anew with cohorts of similarly-armed legionaries. His aim was for each legion to be a self-contained fighting force. Therefore, of the 6,000 men in each legion, 4,800 were now a standardised variant of the legionary.
This was based on the gladius and pilum-armed armed principes and hastati (though the terms were dropped), with the spear-armed triarii and supporting velites disappearing entirely. From now on, all fighting men in the legion were simply called legionaries, with the remaining 1,200 men being support staff. The next military reformation was carried out by Augustus in the late 1st century BC, covering every aspect of the armed forces of Rome.
His first move with the legions was to tackle the huge number he had inherited from the civil wars of which he emerged the victor, in total around 60. He reduced this to 28 (this falling to 25 after Varus’ losses in Germany in 9 AD), and the total would hover around 30 for the next 200 years, for example 29 at the time of the accession of Marcus Aurelius and Lucius Verus in 161 AD.
He then rationalised their organisation. From that point they comprised 5,500 men, organised into ten cohorts. Of these, the first had five centuries of 160 men (later the Severan legio II Parthica’s first cohort had six such centuries), with the other cohorts having six centuries of 80 men. Additionally, the legion also featured 120 auxiliary cavalry acting as dispatch riders and scouts, and support staff.
Marian / Augustan armour
The defensive equipment of the Marian and Augustan legions was a natural evolution of their Camillan and Polybian forebears. In terms of the helmet, the traditional Republic Roman Montefortino type was still in use when Augustus became Emperor, though the mid-Republican Etrusco-Corinthian and Attic types had disappeared by then.
However two new types had appeared in the generation before Augustus, reflecting a Celtic influence following Caesar’s campaigns in Gaul (and following the earlier assimilation of the Celtic mail shirt).
These were the Coolus type with a round cap of bronze and small neck guard (which disappeared in the middle of the 1st century AD), and iron Port type with a deep neck guard, the latter named after the site type location of Port bei Nidau in Switzerland. This latter developed into the classic ‘Imperial’ Gallic helmet often associated with the Roman legionary of the 1st and 2nd centuries AD, featuring an even larger neck guard.
A final ‘Imperial’ type was that originating in Italy, hence it being called Italic, a bronze compromise between the new designs of Celtic origin and the more traditional Roman types. All of these helmets featured prominent cheek guards (again of Gallic provenance) and often a reinforcing strip on the front of the cap to deflect downward sword slashes. Ear guards had been added by the AD 50s.
In terms of armour, the late Republic and early Principate legionaries continued to wear the ubiquitous lorica hamata chain mail short. However, from 9 BC a major change began to take place which was to see the emergence into popular legionary use of the armour most associated in the public mind with the Roman legionary. This was the famous lorica segmentata banded iron cuirass, constructed of articulated iron plates and hoops.
Lorica Segmentata
Such armour appears, unusually, to have been a purely Roman innovation with no cultural influence from opponents or allies. With time, this complicated though highly effective armour was simplified for ease of use by the legionary. One example found at the principia (headquarters building) at the vexillation fortress of Newsteads (Roman Trimontium) in 1905 for instance features simple rivets to replace earlier bronze hinges, a single large girdle plate replacing the two previous ones and strong hooks replacing earlier and more complicated belt-buckle fastenings.
Simplification of this armour continued through to its demise in the later 3rd century AD. The lorica hamata continued to be used alongside it, as did the lorica squamata scale mail shirt. The latter was cheaper than chainmail but inferior in flexibility and protection. Additionally, when fighting certain types of opponent (such as Dacians using the two handed falx slashing weapon) extra armour was fitted including articulated iron manicae arm guards, thigh guards and greaves.
Specific troop types within the legions were also often differentially equipped with armour when compared to the rank and file legionaries to mark them apart, with officers frequently shown wearing iron and bronze muscled cuirasses.
The defensive panoply of the Marian and Augustan legionary was completed with their shield, still the scutum though as time progressed this became squarer in design. In defence this allowed the legionaries to adopt a number of defensive formations, including the testudo. This featured interlocking shields providing full cover on all sides, including from above.
Such traditional legionary equipment remained in use throughout much of the Principate. By the late 2nd/ early 3rd centuries AD however, this was beginning to change.
Later reforms to the legionary
This was largely a response to a change in the nature of their opponents. Previously, the legions had most often faced a similar infantry-heavy force (excepting the Parthians in the east), but were now tackling a multitude of threats, many of a differing nature which required a more flexible response. This change is shown in real time on three of the monuments set up in Rome by three great warrior Emperors – the Column of Marcus Aurelius and the Arches of Septimius Severus and Constantine, with weapons considered first to provide context.
From the reign of Septimius Severus a great change began with the sword, the longer cavalry-style spatha beginning to replace the shorter gladius for all Roman foot soldiers. This was up to 80cm in length, although some of one metre-length have been identified. It seems likely the adoption of this weapon had its origins in a need for more reach to tackle armoured mounted opponents. A similar change is also evident in the use of the pila, they gradually being replaced by a thrusting spear of between 2m and 2.7m in length in the same time period.
This change is visible actually taking place on the three monuments detailed above. Thus on the Column of Marcus Aurelius legionaries in classic lorica segmentata are mostly armed with pila, while on the Arches of Severus and Constantine they have been replaced by spears.
This was again a response to the experiences in fighting mounted opponents more frequently, as with the longer sword. In this regard, Rome had long engaged with Parthian heavy shock cavalry and supporting horse archers in the east, but in the Marcommanic Wars under Marcus Aurelius and Lucius Verus they also found themselves fighting against the Iazyges Sarmatian tribe who had a much higher proportion of mounted shock troops.
A legionary spear wall would therefore have made much more sense engaging such opponents than the use of pilum impact weapons. This change is also evident in the defensive panoply. For example, as the Principate progressed, legionary helmets became increasingly substantial, with the Italic ‘Imperial’ type disappearing in the early 3rd century AD.
Equipped to meet any challenge
By this time many legionaries were being equipped with heavier, single bowl designs reinforced by cross-pieces and fitted with deep napes, meaning only a minimal T-shaped face opening. These provided exceptional levels of protection, especially against mounted opponents.
Not surprisingly, a change is also evident in the body armour of the legionary as the Principate approached its end. Thus on the Column of Marcus Aurelius most are wearing lorica segmentata, while on the Arch of Septimius Severus there is a much higher proportion wearing lorica hamata chain mail, this proportion increasing yet again the Arch of Constantine. Finally, as the 2nd century AD progressed the traditional scutum began being replaced by a large flat (and sometimes slightly dished) oval shield, confusingly still called a scutum.
This new design was of simple plank construction, with stitched-on rawhide, and was strengthened with iron bars. The two types appear to have been used side by side for some time, with examples of both found at the fortified frontier trading town of Dura-Europos in Syria dating to AD 256. This transition is also very evident on the three monuments detailed above, with many of the large round shields featuring on the Severan arch, and even more on the Arch of Constantine.
Once again this change seems associated with the type of opponent more commonly being faced, the round shield perhaps more suited to dealing with a mounted threat. It certainly gave greater freedom of movement for the new swords and spears coming into use with their greater reach, and would also have been cheaper to produce.
To conclude, the defensive equipment of the legionary evolved over the centuries, reacting to the nature of each new threat faced and the Romans adopting military technology when it suited a need. Such flexibility in terms of the legionary’s defensive (and indeed offensive) panoply ensured that the legions were always best equipped to meet any future challenge.