Top 15 Roman Commanders – #9: Gaius Marius


We march along with another commander Rome Across Europe thought was among the best in ancient Rome. You can find the entire list here, along with biographies of #1, #2, #3, #4, #5, #6 , #7 and #8. We now present to you…

9: Gaius Marius (157 – 86 BC)


Gaius Marius was a Roman General and Statesman. He held the office of Consul an unprecedented 7 times during his career. He was also noted for his important reforms of Roman Armies, authorizing recruitment of landless citizens, eliminating the manipulus military formations, and reorganizing the structure of the Legios into separate Cohortes.

Marius was born in 157 BC in the town of Arpinum in southern Latium. The town had been conquered by the Romans in the late 4th Century BC and was given Roman citizenship without voting rights. Only in 188 BC did the town receive full citizenship.

Claims have been made that Marius’ father was a laborer, but this is almost certainly false since Marius had connections with the nobility in Rome. Marius ran for local office in Arpinum, which a laborer’s son could not have done, and he had marriage relations with the local nobility in Arpinum.

This combination indicates that he was born into a locally important family in the Ordo Equester. The problems he faced in his early career in Rome show the difficulties that faced a “New Man” (Novus Homo).

There is a legend that as a teenager Marius found an eagle’s nest with 7 chicks in it. Eagle clutches hardly ever have more than 3 eggs, even if multiple females used the same nest. Finding 7 offspring in a single nest would be exceptionally rare.

Since the eagle was considered the sacred animal of Jupiter, the supreme god of the Romans, it was later seen as an omen predicting his 7 time election as Consul. Later, as Consul, he decreed that the eagle would be the symbol of the Senate and People of Rome.3rd Founder

In 134 BC, he was serving with the Army at Numantia and his good services brought him to the attention of Publius Cornelius Scipio Aemilianus Africanus. According to Plutarch, during dinner the conversation turned to Generals and someone asked Scipio Aemilianus where the Roman people would find a worthy successor to him.

Aemilianus then gently tapped on Marius’ shoulder, saying: “Perhaps this is the man.” It would seem that even at this early stage in his military career, Marius had ambitions for a political career in Rome. He ran for election as 1 of the 24 special military Tribunii of the primary 4 Legios who were elected.

In 114 BC, Marius’ Imperium was postponed and he was sent to govern Lusitania, where he engaged in some sort of minor military operation. According to Plutarch, Marius cleared away the robbers whilst robbery was still considered a noble occupation by the local people.

In 109 BC, Quintus Caecilius Metellus took Marius with him as his Legatus on his campaign against Jugurtha. In the accounts of Metellus’ campaign no other Legates are mentioned, so it can be presumed that Marius was Metellus’s only Legati, or 2nd in Command.In Aquilae

By 108 BC, Marius conceived the desire to run for Consul and soon earned the respect of the troops by his conduct towards them. Marius would eat his meals with the troops and share in any of their labors.

Under these circumstances, Marius was triumphantly elected Consul for 107 BC. He was campaigning against Metellus’s apparent lack of swift action against Jugurtha.

Because of repeated military debacles from 113 BC to 109 BC, it became easier for the virtuous New Man to be elected as an alternative to the inept or corrupt nobility. In accordance with the provisions of the Lex Sempronia on Consular provinces, the Senate decided not to make the war against Jugurtha and to delay Metellus in Numidia.


Marius used a ploy from 131 BC in which a Tribune had passed a law authorizing an election to select the commander for the war against Aristonicus in Asia. A similar law was passed in 108 BC and Marius was voted the command by the people in this special election.

The most dramatic and influential changes Marius made to the Roman army were named the Marian Reforms. In 107 BC Consul Marius, fearing barbarian invasion, saw the dire need for an increase in troop numbers.marius2

Until this time, the standard requirements to become a Roman soldier were very strict. To be considered a soldier in the service of the Republic, an individual was required to provide his own arms and uniform for combat.

Marius relaxed the recruitment policies by removing the necessity to own land, and allowed all Roman citizens entry, regardless of social class. The benefits to the army were numerous, with the unemployed masses enlisting for military service alongside the more fortunate citizens.

Poorer citizens were drawn to lifelong service, as they were rewarded with the prospect of settlement in conquered land. This also ‘Romanized’ the population in newly subjugated provinces, thus reducing unrest and lowering the chance of revolt against the Roman Republic.

The new Roman Army, its numbers vastly bolstered by lower class citizens whose future was tied to their permanent career, was always able to provide reserves in times of disaster. In addition, the growth of the army ensured continued military success due to the high number of recruits available for each campaign.

Marius found that it wasn’t as easy to end the war as he had claimed. He arrived comparatively late in 107 BC. In that year and the next he forced Jugurtha to the south and west toward Mauretania.

By 105 the King of Mauretania, Bocchus I, who was also Jugurtha’s father-in-law and reluctant ally, was worried about the approaching Romans. After receiving word that an accommodation with them was possible, Bocchus insisted that Sulla, Marius’ 2nd in Command, make the hazardous journey to his capital.

Sulla induced Bocchus to betray Jugurtha, who was duly handed over to Sulla, thus ending the war. Since Marius held the Imperium and Sulla was acting as his subordinate, the honor of capturing Jugurtha belonged strictly to Marius.

Marius became the hero of the hour, and his services would be needed in another emergency. The arrival of the Cimbri in Gaul in 109 BC and their complete defeat of Marcus Junius Silanus had resulted in unrest among the Celtic tribes recently conquered by the Romans in southern Gaul.

In 107 BC the Consul was completely defeated by the Tigurini clan. The next year a different Consul, marched to Gaul and captured the disloyal community of Tolosa (Toulouse).Caius_Marius_Amid_the_Ruins_of_Carthage

The Germanic tribes of the Cimbri and the Teutones combined forces and routed the Roman Army on 6 October 105 BC at Arausio. Since the Romans fought with the Rhône at their back, flight was not possible and reportedly 80,000 were killed.

In late 105 BC Marius was again elected Consul while still in Africa because news of the advancing Cimbri on Rome caused an emergency. He returned to Rome by 1 January 104 BC, when he celebrated his Triumphus over Jugurtha.

The Cimbri conveniently marched into Hispania and the Teutoni milled around in northern Gaul, leaving Marius to prepare his army. Marius seems to have been able to get exactly what he wanted, and it even seems that his support determined whom the people would elect as his colleagues.

Finally in 102 BC the Cimbri, together with the Teutones, decided to invade Italy. The Teutones were to head south and advance toward Italy along the Mediterranean coast, while the Cimbri were to attempt to cross the Alps into Italy from the north by the Brenner Pass.marius3

The allied Celtic tribe the Tigurini was to cross the Alps from the northeast. This decision proved fatally flawed.

The Germanic soldiers divided their forces, making each contingent manageable, and the Romans could use their shorter lines of communication and supply to concentrate their forces at will.

First, Marius had to deal with the Teutones, who were in the province of Gallia Narbonensis marching toward the Alps. He refused to give them a battle where they wanted, and withdrew to Aquae Sextiae to block their path.

The leading contingent of the Germanic warriors, the Ambrones, foolishly attacked the Roman position without waiting for reinforcements and 30,000 were killed. Marius then hid 3,000 troops in ambush, so when the main Germanic contingent finally attacked, the hidden Roman troops could fall on them from behind.

In the ensuing defeat, the Teutones were completely annihilated, to the number of something over 100,000.

Marius’ colleague Quintus Lutatius Catulus botched the holding of the Brenner Pass, allowing the Cimbri to advance into northern Italy by late 102 BC. Marius was in Rome, being elected Consul for 101 BC and for his Triumphus over the Teutones.The-Defeat-Of-The-Teutons-And-The-Cimbri-By-Gaius-Marius

He prorogued his celebration and marched north to join Catulus. Finally, in the summer of 101 BC a battle was fought at Vercellae in Gallia Cisalpina.

Once again, Roman discipline overcame a larger barbarian force. At least 100,000 barbarians were killed or enslaved. The Tigurini gave up their efforts to enter Italy from the northeast and went home.

Catulus and Marius celebrated a joint Triumph, but in popular thinking all the credit went to Marius, who was praised as the  “Third Founder of Rome.” As a sort of reward Marius was returned as Consul for 100 BC.

Tribune Lucius Appuleius Saturninus had advocated for a bill that gave colonial lands to the veterans of the recent war and offered to lower the price of wheat distributed by the state. The Senate, however, opposed these measures and violence broke out.

The Senate then ordered Marius, as Consul, to put down the revolt. Marius complied with the request and put down the revolt in the interest of public order, and then went into retirement.

With the arrival of the Social War of 90–88 BC, Marius took command and fought against the rebel cities, but retired from the war in its early stages due to poor health. After the Social War, King Mithridates of Pontus began his bid to conquer Rome’s eastern provinces and invaded Greece.

In 88 BC, Lucius Cornelius Sulla, the elected Consul, left Rome and travelled to Nola where he urged his legions to defy the assembly’s orders and accept him as their rightful leader. Sulla was successful and then commanded 6 legions to march with him to Rome and institute a civil war.

This was a momentous event as no Roman army had ever marched upon Rome, not only was it forbidden by law but it was also part of Rome’s ancient tradition. Once it became obvious that Sulla was going to defy the law and seize Rome by force, Marius attempted to organize a defense of the city using gladiators.

Unsurprisingly Marius’ makeshift force was no match for Sulla’s Legios. Marius was defeated and fled Rome.

Marius narrowly escaped capture and death on several occasions and eventually found safety in Africa. Sulla and his supporters in the Senate passed a death sentence on Marius and a few of his allies.Marius_in_exile

Sulla was again confirmed as the commander of the campaign against Mithridates, so he took his legions out of Rome and marched to war. Marius and his son returned from exile in Africa with an army he had raised there, and entered Rome.

Some of Marius’ soldiers went through Rome killing the leading supporters of Sulla. Their heads were exhibited in the Forum Romanum. The Senate then passed a law exiling Sulla, and Marius was appointed the new commander in the eastern war.

In his Life of Marius, Plutarch writes that Marius’s return to power was a particularly brutal and bloody one, saying that the Consul’s “anger increased day by day and thirsted for blood, kept on killing all whom he held in any suspicion whatsoever.”

Marius died on 13 January 86 BC, just 17 days into his 7th Consulship. Marius was a successful Roman General and military reformer, but also known as a harsh, ambitious man harboring contempt for the nobility. He played a critical role in the destruction of the Roman Republic, and the birth of the Roman Empire.

His improvements to the structure and organization of the Roman Legion were profound and effective. The Marian reform, recruiting among un-propertied urban citizens, was a pivotal step leading in short order to the collapse of the Republic.

Marius set the precedent of recruiting among the poor and then granting these veterans land upon the conclusion of the campaign. Thus the legions became more loyal to their Generals than to the State.marius

Having also defeated various invading Germanic tribes, for which he was called the “Third Founder of Rome”. The life and career of Gaius Marius were significant in Rome’s transformation from Republic to Empire.

Thank you for stopping by. Please come back next week as we find out more about Rome Across Europe‘s #10 Top Commander. Until then, Don’t Stop Rome-ing!



Appianus.  The Civil Wars.  Trans. John MacKenzie Carter.  Penguin, 1996.

D’Arms, John H. “The Campanian Villas of C. Marius and the Sullan Confiscations”, The Classical Quarterly, Vol. 18, No. 1. (1968), pp. 185–188.

Hazel, John.  Who’s Who in the Roman World.  Psychology Press, 2002.

Plutarch.  Life of Marius.  Trans. Rex Warner.  Penguin, 2005.

Trabex, Winter. From Republic to Empire: The Decline of Roman Power.

Warry, John.  Warfare in the Classical World.  Salamander, 1980.

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