When we go a couple of millennia back, ancient Rome ruled over much of Europe, Africa, and western Asia. The formidable might and efficiency of ancient Roman military played a pivotal role in the rapid expansion of contemporary Roman civilization. A part of the Roman military power, the Roman legions formed the largest units in the Roman army. Each legion consisted of around 3000 well-trained men during the early republic days. This number was later expanded to adjust up to 5200 men in each legion during the Imperial era. A typical Roman legion would have 10 cohorts (about 5000 men). This changed around the second half of the first century when the number was kept at nine cohorts of standard size. Each legion was then assigned one for the cohort with twice the strength in terms of number and skills. Throughout the ancient Roman history, a number of such Legions were formed, led into numerous conflicts and wars, and then ultimately disbanded. Here is a list of top 10 Roman legions.
10. Legio III Gallica
Legio III Gallica or simply the Third Gallica Legion was founded by Gaius Julius Caesar around 49 BC. He formed this legion to specifically get much needed offensive assistance in the civil war he has perpetrated against the conservative republic Romans led by Pompey. Since the legion’s cognomen (the third name) Gallica seemingly originates from the word “Gaul”, it is assumed that most of the Gallica recruits must have been from Gaul. The legion had a bull as its symbol (as did pretty much every legion formed under Julius Caesar). The Gallica helped Caesar carry out major campaigns against the republic, the highlights being battles of Pharsalus and Munda.
Historians also state that later on, the Roman power-holders might have decided to send a part of the legion to the vassal king Herod of Judaea. The sent force was to assist the king in reclaiming his kingdom of Judaea. After the fall of Caesar, almost the entire third Gallica legion was handed over to Mark Antony to assist him in the battles against Parthians. It is said that the brave men of Gallica legion fought gallantly against the far stronger might of Parthians. They eventually had to retreat but not before having saved the rest of the Roman army already engaged in the battle.
9. Legio VI Victrix
The ‘Victorious Sixth Legion’ was founded by general Octavian (who later went on to become emperor Augustus) around 41 BC. This rather famous legion in the history of Imperial Roman army was considered to be a twin of the much revered Legio VI Ferrata. The legion saw its first action in 41 BC right around its formation when it fought alongside Octavian at Perusia in his campaign against Mark Antony’s wife and brother. The Victrix played a crucial role in bringing down Antony and Cleopatra to their knees by running through their opponents during the Pannonian campaigns in 39-36 BC. Perhaps the biggest blow to any chances of Antony and Cleopatra claiming the empire came when Legio Vi Victrix, along with other legions, defeated the enemy in the battle of Actium.
The Victrix legion then went on to assist Augustus in his war against the Cantabrians that went on for almost 10 years starting from 29 BC. By 19 BC, the Imperial Rome had conquered entire Hispania and the Iberian Peninsula was also now under the Roman rule. The legion was then stationed in the freshly conquered contemporary Spain where they stayed for nearly a century. During this time, they founded the city of Legio (known as Leon in present day).
8. Legio XVIII
Legio duodevigesima or simply the Eighteenth Legion was also founded in 41 BC, again, by soon-to-be emperor Augustus. Historians believed Augustus formed this legion to deal with Sextus Pompeius who was then stationed in Sicily and was one of the last formidable opposition to Augustus’ campaign. Pompeius had a slight upper hand in the conflict since his prolonged occupation of Sicily meant he could easily block much of Roman grain supply.
But as it happens, the Eighteenth legion, along with Legio XVII and Legio XIX faced a crushing defeat in the Battle of Teutoburg Forest. Legio XVIII was absolutely destroyed with last pieces of the legion’s symbol and cognomen obliterated and unknown to this day. Some historians also state that Legio XVIII might have been among the group of eight legions Mark Antony was supposed to have from Augustus in his campaign against Parthians. But Augustus never delivered on his promise.
7. Equestris Legion
The Legio X Equestris or the Tenth Mounted Legion was enlisted by Julius Caesar in 61 BC during his governor days at Hispania Ulterior. Around the time when Caesar started his governing duties at Hispania, he realized he was one more legion short to kick off his carefully constructed campaign. That is when he formed the Equestris legion, the first legion Caesar levied personally, and one that proved to be the most trustworthy. In around 58 BC, Caesar ordered the legionaries of Tenth to ride on horses because he hasn’t had much faith in his Gallic cavalry auxiliaries. Then on, the Tenth Legion got its new cognomen and went on to be known as Legio X Equestris.
The Equestris Legion were in thick of the action when the Gallic war broke out. In fact, they have involved in pretty much each war Caesar declared upon his enemies. It was the composure and bravery of Tenth Equestris Legion that brought about the defeat of Helvetii tribes. Because of wins on this front, the Romans were able to blockade any of Helvetii from moving into contemporary western France.
6. Legio XII Fulminata
Legio duodecima Fulminata or simply the ‘Thunderbolt Twelfth Legion’ was a famous legion from the days of Imperial Rome. I was also known by the cognomens Paterna, Antiqua, Certa Constans and Galliena. The legion was enlisted by Caesar in 58 BC with his sights set on scoring a thumping victory in the Gallic wars. The Fulminata legion fought in the war for Caesar till 49 BC. Immediately next came another war Caesar declared on Triumvir and Pompey around January, 49 BC. The Fulminata legion was actively engaged in the full-scale invasion of Italy, and also in the Battle of Pharsalus on August 9, 48 BC.
The Twelfth Fulminata had a thunderbold as its emblem. Once the majority of conflicts were over and the legion had helped Caesar achieve an all-around victory in grabbing power of the Imperial Rome, the legionnaires were pensioned off and given lands in the neighborhood of Parma. Though the legion must have been levied again sometimes later as this unit has been documented to have been guarding the crossing of Euphrates river as later as the beginning of 5th century.
5. Legio III Cyrenaica
Cyrenaica legion was active in different shape and size from its formation in 31 BC all the way up to the early years of 5th century. From the Battle of Actium in 31 BC to one of the many Jewish Revolts during 132 – 136 AD, the Cyrenaica legion had an influential presence in major incidents of ancient Roman history. The reason behind its cognomen isn’t exactly known, but many believe it took the name ‘Cyrenaica’ to signify its origin in Cyrene (Present day Libya). The name could also have been given to mark some of its notable achievements in that region.
Regardless of all the mystery shrouding its inception, Legio III Cyrenaica was definitely used by emperor Augustus to maintain control over contemporary Egypt which he has annexed around 30 BC. Then onward, historians state that the legion was under the command of either Lepidus or Marc Antony – both being members of Second Triumvirate. The legion went on to stay in Egpyt for more than a century and a half and became so adapted to the Egyptian culture that many of Cyrenaica legionnaires had started to worship Egyptian god of Ammon.
4. Macedonica Legion
It was in 48 BC when Caesar had flamed a civil war by crossing the Rubicon River a year before. Much of the conservative Roman republicans had fled to Greece. Caesar was preparing a full-on assault on the republicans and that is when, along with a handful of other ‘first’ units, he formed the Legio IV. The Legio IV got its first taste of action in the battles of Dyrrhachium and Pharsalus where Caesar scored a decisive victory over Pompey. The legion was then settled in the province of Macedonia whereon it became known as the Macedonica Legion.
Soon, Caesar enlisted the Macedonica legion to fight in his campaign against the Parthians. But right around this time, he was brutally murdered and the plans of the Parthian invasion were called off. Marc Antony seized the opportunity to tap in the Macedonica legion force at hand and actively involved them for his campaigns in eastern Italy. However, this pact soon fell over when Legio IV decided to side with Octavian and fought against Antony in the battle of Modena in April, 43 BC. Soon, Octavian became Emperor Augustus and had the Legio IV sent to take part in decisive battles of Cantabrian Wars and Vellica in 30 and 25 BC respectively.
3. Hispana Triumphalis Legion
Originally known as the Legio IX Hispania, the Hispana Legion was amongst the first of legions formed by Julius Caesar during his campaigns against the Roman Republic. The Legio IX fought valiantly alongside compatriot legions VII, VIII and X during the invasion of Gaul in 58 BC. It has been documented that the Roman commander has particularly impressed by the bravery and heroics of Legio IX in the battle against Nervians. When Caesar fell, the legion was again levied into Roman military by his heir Octavian. Commander Octavian immediately put them into annexing the city of Sicily which was then under the control of his arch enemy Sextus Pompeius. The Legio Hispana Triumphalis, along with other legions enlisted in the campaign by Octavian, soon brought entire Sicily under Roman regime.
Once Sicily was annexed, Octavian declared himself the emperor and became Augustus. He also sent the Ninth legion to maintain control of the Balkans. It was around 43 AD when the legion was brought back to action in the Roman invasion of Britain. It is very likely that Legio IX Hispania assisted in the battle against Brits with Rome then under the rule of Emperor Claudius. Historians state that the legion suffered a massive defeat in Battle of Camulodunum that occurred amid the infamous rebellion of Boudica. A huge chunk of legionnaires was killed and whatever force remained was then used to reinforce the Germania provinces.
2. Germanica Legion
Founded by Julius Caesar to bolster his warring campaign against Pompey, the Legio I Germanica or simply the first Germanic Legion was enlisted in 48 BC. Contrary to the popular belief that it got the Germanica cognomen because the origin of its soldiers was Germany, almost all the Germanica legionnaires were Roman. It was their outstanding service in the contemporary Germany that earned them the said cognomen. At around 41 BC, the legion became a part of Octavian’s army and clashed in the war against Sextus Pompeius. The Germanica legion then took part in a decade long conflict against the Cantabrians under the leadership of Augustus.
Together with the Second Augusta Legion, Germanica helped build a whole new colonia of Acci in Spain during the same period of time. Once the conflict was settled, much of the legion’s veterans retired in present day Barcelona and Tenes, Algeria. Of course, new recruits were regularly enlisted and soon the legion was stationed to defend the Rhine where, historians suggest, Germanica might have helped Tiberius in his war against the Celtic Kingdom of Vindelicia. The First Germanica Legion remained active from the year of its formation up to the waning days of 70 AD. The legion was disbanded by Emperor Vespasian and whatever force remained was merged into Legio VII Gemina.
1. Augusta Legion
Also known by the name Legio II Augusta, one can easily conclude that this famous legion got its cognomen from the legendary emperor of Imperial Rome, Augustus himself. It is rather unclear if the legion was actually formed by Augustus himself during his commandeering days or he put together an already existing legion as Legio II Augusta into his army. The first known documentation of Augusta dates back to around 26 BC, when it took on the Cantabrians alongside seven or more legions in the Cantabrian Wars of 29 to 19 BC. Once the war was won, like other legions, Augusta legionnaires also stationed themselves in Spain.
When the era of Imperial Rome embarked, Legio II Augusta stood true to its cognomen and swore its allegiance to Augustus. The legion was a formidable force in the Battle of Actium that took place in the year of 31 BC. Afterwards, it seems a huge part of legion was dissolved and much of its legionnaires were sent on leave or retirement. But the legion was enlisted again for the battle against Brits in 43 AD. The Augusta legion held the Roman might in the brutal battles against Durotriges and Dumnonii tribes under the leadership of emperor Vespasian. The legion has also been noted to have helped build the Hadrian’s Wall in 122 AD and Antonine Wall in 142 AD.
This list quite evidently shows that Julius Caesar was responsible for the enlisting of oldest legions towards the start of Imperial Roman era. Octavian (later Emperor Augustus) mostly took off from where Caesar left to get hold of legions at his disposal only to further reinforce their might in the ancient Roman military. They had a certain panache of engaging in almost omnipresent warfare – participating in one battle after another at times. More often than not, they played decisive roles in battles despite massive losses and odds heavily stacked against them. These legions fought in countless battles and conflicts whose outcomes helped shaped the Roman history as we know it today.