Gaius Marius

Gaius Marius (/ˈɡaɪəs ˈmɛəriəs, ˈmær-/, [ˈɡaː.ɪ.ʊs ˈmarɪ.ʊs]; 157 BC – 13 January 86 BC) was a Roman general and statesman. Victor of the Cimbric and Jugurthine wars, he held the office of consul an unprecedented seven times during his career. He was also noted for his important reforms of Roman armies. He was at the centre of a paradigmatic shift from the militia levies of the middle Republic to the professional soldiery of the late Republic; he also improved the pilum, a javelin (after improvement) designed to bend on impact, and large-scale changes to the logistical structure of the Roman army.

For his victory over invading Germanic tribes in the Cimbrian War, he was dubbed "the third founder of Rome". His life and career, by breaking with many of the precedents that bound the ambitious upper class of the Roman Republic together and instituting a soldiery loyal not to the Republic but to their commanders, was highly significant in Rome's transformation from Republic to Empire. In the realm of politics he helped lead the Populares faction against the Optimates of Lucius Cornelius Sulla, their rivalry coming to a head in 88–87 BC during Sulla's first civil war. A year later Marius died of natural causes during his seventh consulship.

Early career

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, thirty years before his birth, did the town receive full citizenship. Although Plutarch claims that Marius' father was a labourer, this is almost certainly false since Marius had connections with the nobility in Rome, he ran for local office in Arpinum, and he had marriage relations with the local nobility in Arpinum, which all combine to indicate that he was born into a locally important family of equestrian status. While many of the problems he faced in his early career in Rome show the difficulties that faced a "new man" (novus homo) in being accepted into the stratified upper echelons of Roman society, Marius – even as a young man – was not poor or even middle class, he was most assuredly born into inherited wealth gained, most likely, from large land holdings. In fact, his family's resources were definitely large enough to support not just one member of the family in Roman politics: Marius' brother, Marcus Marius, would also enter Roman public life.

There is a legend that Marius, as a teenager, found an eagle's nest with seven chicks in it – eagle clutches hardly ever have more than three eggs; even if two females used the same nest – and finding 7 offspring in a single nest would be exceptionally rare. Since eagles were considered sacred animals of Jupiter, the supreme god of the Romans, it was later seen as an omen predicting his election to the consulship seven times.Later, as consul, he decreed that the eagle would be the symbol of the Senate and People of Rome.

In 134 BC, he joined the personal legion of Scipio Aemilianus as an officer for the expedition to Numantia. It is unclear whether or not Marius was already present and serving in Numantia with the previous commander, Quintus Pompeius, the consul for 141 BC, when Aemilianus arrived. However it is, while he was serving with the army at Numantia, his good services brought him to the attention of Scipio Aemilianus. According to Plutarch, during a conversation after dinner, when the conversation turned to generals, someone asked Scipio Aemilianus where the Roman people would find a worthy successor to him, the younger Scipio gently tapped on Marius' shoulder, saying: "Perhaps this is the man".

It would seem that even at this early stage in his army career, Marius had ambitions for a political career in Rome. According to Plutarch, as a hereditary client of the Caecilii Metelli, one of the noble families which was then emerging as the dominant faction in Rome, Marius ran for election as one of the twenty-four special military tribunes of the first four legions who were elected (the rest were appointed by the magistrate who raised the legion). Sallust tells us that he was unknown by sight to the electors but was returned by all the tribes on the basis of his accomplishments. After election, he likely served in the Balearic Islands helping one of the Caecilii Metelli win a triumph.

Next, he possibly ran for the quaestorship after losing an election for local office in Arpinum. The military tribunate shows that he was already interested in Roman politics before the quaestorship. Perhaps he simply ran for local office as a means of gaining support back home, and lost to some other local worthy. It is possible, however, that Marius never ran for the quaestorship at all, jumping directly to plebeian tribune. He likely, however, participated in the major Roman victory of 121 BC which permanently cemented Roman control over southern Gaul.

In 120 BC, Marius was returned as plebeian tribune for the following year. He won with the support of the Metelli faction, specifically Lucius Caecilius Metellus Dalmaticus. According to Plutarch, the Metelli were one of his family's hereditary patrons; while this connection may be a latter-day exaggeration, it was not uncommon for prospective consuls to campaign for their candidates for the tribunate and lower the possibility of opposition tribunes exercising their vetoes.

According to Plutarch, against the wishes of his patrons, he pushed through a law that restricted the interference of the wealthy in elections. In the 130s, voting by ballot had been introduced in elections for choosing magistrates, passing laws and deciding legal cases, replacing the earlier system of oral voting. The wealthy continued to try to influence the voting by inspecting ballots and Marius passed a law narrowing the passages down which voters passed to cast their votes in order to prevent outsiders from harassing the electors. It is not clear, however, whether Plutarch's narrative history properly reflects how controversial this proposal in fact was: Cicero, writing at least during the Republic, describes this lex Maria as quite straightforward and uncontroversial. But while the election procedures were supported by the plebs in Rome, Marius shortly thereafter alienated them by vetoing a bill for the expansion of the ever-popular grain dole, citing high cost.

Soon thereafter, Marius ran for the aedileship in 117 BC and lost. It seems clear that by this time, simply due to the enormous financial difficulties that any prospective aedile would have to shoulder, Marius had either amassed or was availed of significant financial resources. This loss was at least in part due to the enmity of the Metelli. In 116 BC he barely won election as praetor for the following year, coming in last, and was promptly accused of ambitus (electoral corruption). Being accused of electoral corruption was common during the middle and late Republic and details of the trial are sketchy or apocryphal. Marius, however, was able to win acquittal on this charge, and spent an uneventful year as praetor in Rome, likely as either praetor peregrinus or as president of the corruption court. In 114 BC, Marius' imperium was prorogued and he was sent to govern the highly sought-after province of Further Spain (Latin: Hispania Ulterior), where he engaged in some sort of minor military operation to clear brigands from untapped mining areas. Due to his success in Spain, Marius almost certainly returned to Rome in 113 BC with his personal wealth greatly enlarged.

He received no triumph on his return, but he did marry Julia, the aunt of Julius Caesar. The Julii Caesares were a patrician family, but at this period seem to have found it hard to advance above the praetorship. The Julii had done so only once in the 2nd century, in 157 BC. The match was advantageous to both sides: Marius gained respectability by marrying into one most ancient patrician families in the Republic and the Julii received a great injection of energy and money. Sources are unclear on whether Marius joined the annual race of former praetors for the consulship, but it is likely that he failed to be elected at least once.

Subordinate to Metellus

The Jugurthine War started due to "Roman exasperation with the ambitions of Jugurtha", who had killed his half-brothers, massacred Italians in his civil war against them, and bribed many prominent Romans to support him in the Senate. After the start of hostilities, the first army sent to Numidia was apparently bribed to withdraw and the second army was defeated and forced to march under the yoke. These debacles eroded trust in the ability for the aristocracy to adequately manage foreign affairs.

While Marius had seemingly broken with the Caecilii Metelli during his time as tribune and praetor, the Metellii did not seem to hold this rupture against him so much as to pass over him for selection as legate in the opening phases of the Jugurthine War. In 109 BC, likely to improve his chances for the consulship, Marius joined then-consul Quintus Caecilius Metellus, in his campaign against Jugurtha. Legates (legati) were originally simply envoys sent by the Senate, but men appointed as legates by the Senate were used by generals as subordinate commanders, usually becoming the general's most trusted lieutenant. Hence, Metellus had to have asked the Senate to appoint Marius as legate to allow him to serve as Metellus' subordinate.

In Sallust's long account of Metellus' campaign no other legates are mentioned, so it is assumed that Marius was Metellus's senior subordinate and right-hand man. Metellus was using Marius' strong military experience, while Marius was strengthening his position to run for the consulship.

During the Battle of the Muthul Marius' actions probably saved the army of Metellus from annihilation. Jughurtha had cut the Romans off from the River Muthul where they wanted to refill their water reserves. The Romans had to fight Jugurtha in the desert where the Numidian light cavalry had an advantage. The Numidian cavalry scattered the Romans into small detachments and soon had control of the battle field. Each group of Romans was fighting for their survival. At this point Marius re-organized a few detachments, and led a column of 2,000 men through the Numidans and linked up with Metellus. Together they led their men against the Numidian infantry who occupied a hill. After gaining control of the hill Marius and Metellus led their men against the rear of the Numidian cavalry. The Romans gained the initiative and the Numidians had no choice but to withdraw.

Run for the consulship

By 108 BC, Marius expressed his desire to run for the consulship. Metellus did not give Marius his blessing to return to Rome, allegedly advising Marius to wait and run with Metellus's son (who was only twenty, which would signify a campaign 20 years in the future), Marius began to campaign for the consulship.Sallust claims that this was catalyzed, in part, by a fortune-teller in Utica who "told him that great and wonderful things were presaged to him that he might therefore pursue whatever designs he had formed trusting to the gods for success, and that he might try fortune as often as he pleased for that all his undertakings would prosper."

Marius soon earned the respect of the troops by his conduct towards them, eating his meals with them and proving he was not afraid to share in any of their labours. He also won over the Italian traders by claiming that he could capture Jugurtha in a few days with half Metellus's troops. Both groups wrote home in praise of him, suggesting that he could end the war quickly unlike Metellus, who was pursuing a policy of methodically subduing the countryside.

In early 109 BC, a detachment of Roman soldiers serving as the garrison of Vaga was ambushed and cut down almost to a man. The commander of the garrison, one Titus Turpilius Silanus, a client of Metellus, escaped unharmed. Marius allegedly urged Metellus to sentence Silanus to death on charges of cowardice, but then apparently turned on Metellus, arguing that the sentence was disproportionate and overly harsh. Also sending letters back to Rome claiming that Metellus had become enamoured with the unlimited powers associated with his imperium, Metellus, wary of an increasingly disgruntled and resentful subordinate, permitted Marius to return to Rome. According to Plutarch, with barely enough time to make it back for the consular elections; but according to Sallust, enough time to effectively canvass for votes.

With growing political pressure towards a quick and decisive victory over Jugurtha, Marius was elected consul for 107 BC, campaigning against Metellus's apparent lack of swift action against Jugurtha, with Lucius Cassius Longinus as his colleague. Because of the repeated military debacles from 113 BC to 109 BC and the accusations that the ruling oligarchy was open to flagrant bribery, it became easier for the virtuous new man who had worked with difficulty up the ladder of offices to be elected as an alternative to the inept or corrupt nobility.

The Senate prorogued Metellus' command in Numidia, thereby preventing Marius from assuming command. Yet, Marius got around this by inducing an ally of his, then-tribune Titus Manlius Mancinus, to have the Assembly override the Senate's decision and appoint him in command. Metellus shed bitter tears when he learned of the decision; refusing to personally hand over command to Marius, Metellus was surprised at a positive welcome. Metellus' family arranged for thronging crowds to greet his ship and induced the Senate to vote Metellus a triumph and the agnomen Numidicus.

War in Numidia

Seeking troops to bolster the forces in Numidia and win his promised quick victory, Marius found that Rome's traditional manpower reserves depleted. As inequality increased, fewer men of military age met the property requirements to serve in the legions. Yet, thousands of poor Italians sat idly in Rome, ineligible to serve. Seeking to use them, and with precedent for waiving the property requirements during the existential crisis that was the Second Punic War, Marius was exempted from the requirements. With more troops mustering in southern Italy, Marius sailed for Africa, leaving his cavalry in the hands of his newly elected quaestor, Lucius Cornelius Sulla.

Marius found that ending the war was more difficult than he had claimed. Jugurtha was fighting a guerrilla war, it appeared that no strategy would work better than Metellus' strategy of denying Jugurtha reinforcement and support. He arrived comparatively late in 107 BC but still fought and won a battle near Cirta. At the end of 107 he surprised Jugurtha by a dangerous desert march to Capsa in the far south where, after the town surrendered, he put all the survivors to the sword. Keeping up the presure he drove Jugurtha's forces southwards and westwards into Mauretania. Marius was supposedly unhappy at receiving the dissolute and libertine Lucius Cornelius Sulla as his quaestor, but he proved a highly competent officer, well liked by the men. Meanwhile, Jugurtha was trying to get his father-in-law king Bocchus of Mauretania to join him in the war against the Romans. In 106 Marius marched his army far to the west, capturing a fortress by the river Molochath. Unfortunately, this advance had brought him near the dominions of Bocchus finally provoking the Mauretanian into action; in the deserts just west of Serif, Marius was taken by surprise by a combined army of Numidians and Mauretanians under the command of the two enemy kings. For once, Marius was unprepared for action and in the melee all he could do was form defensive circles. The attack was pressed by Gaetulian and Mauretanian horsemen and for a time Marius and his main force found themselves besieged on a hill, while Sulla and his men were on the defensive on another hill nearby. However, the Romans managed to hold off the enemy until evening and the Africans retired. The next morning at dawn the Romans surprised the Africans' insufficiently guarded camp and completely routed the Numidian-Mauretanian army. Marius then marched east to winter quarters in Cirta. The African kings harried the retreat with light cavalry, but were beaten back by Sulla whom Marius had put in command of the cavalry. It was by now evident that Rome would not defeat Jugurtha's guerrilla tactics through military means. Therefore, Marius resumed negotiations with Bocchus, who, though he had joined in the fighting, had not yet declared war. Ultimately, Marius reached a deal with Bocchus whereby Sulla, who was friendly with members of Bocchus' court, would enter Bocchus' camp to receive Jugurtha as a hostage. In spite of the possibility of treachery on the Mauritanian's part, Sulla agreed; Jugurtha's remaining followers were treacherously massacred, and he himself handed over in chains to Sulla by Bocchus. In the aftermath, Bocchus annexed the western part of Jugurtha's kingdom, and was made a friend and ally of the Roman people. Jugurtha was thrown into an underground prison (the Tullianum) in Rome, and ultimately died after gracing Marius' triumph in 104 BC.

Since Marius held the imperium and Sulla was acting as his subordinate, the honour of capturing Jugurtha belonged strictly to Marius. But Sulla had clearly been immediately responsible and had a signet ring made for himself commemorating the event. Sulla and his aristocratic allies encouraged this narrative to discredit Marius. This was to be one of the main causes of the eventual rivalry between Marius and Sulla that would end in civil war.

Cimbri and Teutones

The arrival of the Cimbri in Gaul in 109 BC and their complete defeat of Marcus Junius Silanus had crippled Roman prestige, resulted in unrest among the Celtic tribes recently conquered by the Romans in southern Gaul. In 107 the consul Lucius Cassius Longinus was completely defeated by the Tigurini, and the senior surviving officer (one Gaius Popillius, son of the consul of 132) had saved what was left only by surrendering half the baggage and suffering the humiliation of having his army "march under the yoke". The next year, 106 BC, another consul, Quintus Servilius Caepio, marched to Gaul with another new army to salvage the situation. There, he captured the town community of Tolosa (modern day Toulouse), where he discovered a great treasure cache called the Gold of Tolosa, believed to be stolen from the Greek temple of Delphi. It was stolen when being transported to Massilia (modern day Marseille), with Caepio suspected of having organised the theft. While Caepio was prorogued into the next year, the new consul for 105 BC Gnaeus Mallius Maximus, was also assigned to southern Gaul with another army. Caepio's disdain for Mallius, a new man like Marius, and hunger for glory made it impossible for them to cooperate.

The Cimbri and the Teutones (both migrating Germanic tribes) appeared on the Rhône, and while Caepio was on the west bank he refused to come to the aid of Mallius on the left. The Senate was unable to induce Caepio in cooperate with Mallius, which proved both generals' undoing. The Cimbri, at the Battle of Arausio, overwhelmed and overran Caepio's legions with massively overwhelming numbers. Caepio's routed men crashed into Mallius' troops, which led to both armies being pinned against the River Rhône and annihilated by the numerically dominant Cimbrian warriors.

The losses in the preceding decade had been bad enough, but this defeat, apparently caused by the arrogance of the nobility and its refusal to co-operate with talented non-nobles, thoroughly discredited the aristocracy's management of foreign threats. Not only had huge numbers of Romans lost their lives but Italy itself was now exposed to invasion from barbarian hordes.

The Republic, altogether lacking many generals who had recently in fact concluded successfully any recent military campaigns, took the illegal step of electing Marius in absentia for a second consulship in three years. While his election was not unprecedented, as Quintus Fabius Maximus had been elected for consecutive consulships and it was not unheard of for consuls to be elected in absentia, it certainly was not with recent precedent. Yet, since the Assembly had the ability to overturn any law, it simply set aside the requirements and made Marius consul.

As consul

Marius was still in Africa when the Assembly elected him consul for 104 BC. At the start of his consulship, Marius returned from Africa in spectacular triumph, bringing Jugurtha and the riches of North Africa to awe the citizenry. Jugurtha, who had prophesied the purchase and destruction of Rome, met his end in the Roman prison after having been led through the streets of the city in chains. Marius was assigned – it is unclear whether by the Assembly or sortition – the province of Gaul to deal with the Cimbric threat.

The Cimbri, after their decisive victory at Arausio, marched west into Hispania. Marius was tasked with rebuilding, effectively from scratch, the Gallic legions. Basing his army around a core of trained legionaries from the last year, Marius again secured exemption from the property requirements and with his newly-minted reputation for glorious and profitable victory, raised an army of some thirty thousand Romans and forty thousand Italian allies and auxiliaries. He established a base around the town of Aquae Sextiae and trained his men.

One of his legates was his old quaestor, Sulla, which shows that at this time there was no ill-will between them. In 104 BC, Marius was returned as consul again for 103 BC. Though he could have continued to operate as proconsul, it is likely that the people reelected him as consul so to avoid another incident of disputed command à la Caepio and Mallius. 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 (his choice was apparently determined, on several occasions, on the basis of their malleability: only Catulus in 102 BC, and Flaccus in 100 BC, would have been serious candidates in their own right without his support, and even Flaccus was described as more servant than partner in the office).

In 103 BC, the Germans still did not emerge from Hispania, and Marius's colleague died, requiring Marius to return to Rome to call elections. Lacking a decisive conclusion to the Cimbrian conflict over the last two years, it was not a foregone conclusion that Marius would win reelection. To that end, he secured a political alliance with a firebrand populist tribune, Lucius Appuleius Saturninus, who with considerable oratorical skill, helped Marius achieve reelection to the consulship for 102 BC.

Over his successive consulships, Marius was not idle. He trained his troops, built his intelligence network, and conducted diplomacy with the Gallic tribes on the provincial frontiers. And beyond building allies in anticipation for the return of the Cimbri, he executed significant and wide-ranging reforms to the legions.

Over this time, while the Republic raised men and prepared for the Cimbric threat, a slave revolt engulfed Sicily. The revolt was tangentially related to the Republic's attempts to raise more troops by appeasing the Italians by emancipating Italians who had been enslaved for failure to pay tax. In 104 BC, a praetor by the name of Publius Licinius Nerva was instructed to establish a tribunal to identify and emancipate enslaved Italians. The premature closure of the tribunal due to local pressure caused unrest and ignited an uprising that would consume the island until 100 BC.

Reforms to the military

In the years preceding Marius, there was an increasing popular movement for the redistribution of land from the wealthy aristocracy to the urban poor. The Gracchian agrarian reforms had been premised on the traditional Roman levy, which excluded from service those whose property qualification fell below the minimum property qualification for the fifth census class. One of the major arguments for these land reforms was to rebuild the manpower pool from which the legions recruited.

While the Gracchi had tried to restore the smallholders who would constitute the majority of those qualified to serve, their land legislation did little to alleviate the growing manpower shortage that gave rise to that legislation. It seems that the minimum qualification for the fifth census class (the lowest one eligible for military service) was lowered from 11,000 to 3000 sesterces of property, and already in 109 BC the consuls had had to seek suspension of Gaius Gracchus' restrictions on the levy. In 107 BC, Marius was granted authorisation to ignore property qualifications altogether for the war against Jugurtha. And again, with the threat of the Cimbri, he was granted another exemption.

After the repeated disasters of the Cimbrian war, this need for men became ever more acute. Temporary lifting of property requirements became a permanent necessity to combat Rome's adversaries. Marius and his contemporaries' need for soldiers cemented a paradigmatic shift away from the levy-based armies of the middle Republic towards open recruitment. Thereafter, Rome's legions would largely consist of poor citizens (the "capite censi" or "head count") whose future after service could only be assured if their general could bring about land distribution and pay on their behalf. In the broad sweep of history, this reliance on poor men would make soldiers strongly loyal not to the Senate and people of Rome, but to their generals whom would be perceived as friends, comrades, benefactors, and patrons of soldiers.

Marius, however, in his successive consulships, also overhauled the training and logistical organisation of his men. Instead of baggage trains, Marius had his troops carry all their weapons, blankets, clothes, and rations. This led to Roman soldiers of the time being referred to as Marius' mules. He also improved the pilum, a javelin which (after improvement) when thrown and impacting the enemy, would bend so to be unusable. While Marius is credited for many of the reforms in his period, there is no evidence to support the claim that it was Marius who changed the tactical unit of the army from the maniple to the cohort.

Battle with the Germanic tribes

The People's Assembly was nervous enough about the Cimbric threat and disunity in command to reelect Marius to three successive consulships (in 104, in 103 and in 102 BC).

In 102 BC, the Cimbri returned from Hispania and, with a number of other barbarian tribes, invaded Italy. The Teutones and their allies the Ambrones were to head south and advance toward Italy along the Mediterranean coast; the Cimbri were to attempt to cross the Alps into Italy from the north by the Brenner Pass; and the Tigurini (the allied Celtic tribe who had defeated Longinus in 107) were to cross the Alps from the northeast. This decision proved fatally flawed. The Germanic warriors 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 and their allies the Ambrones, who were in the province of Narbonensis marching toward the Alps. He frustrated them by refusing to give battle, and withdrew to a ridge across the river near Aquae Sextiae, which blocked their path. The leading contingent of the Germanic warriors, the Ambrones, attacked the Roman position without waiting for reinforcements, they had to charge uphill while the Romans fought downhill, the Romans had the advantage and 30,000 Ambrones' warriors were killed. Marius then sent 4,000 troops under Manius Aquillius across the river and hid them in an ambush. The next day when the main Germanic contingent finally attacked, the hidden Roman troops would fall on them from the rear. In the ensuing Battle of Aquae Sextiae, the Teutones were completely annihilated, suffering somewhere between 100 thousand and 200 thousand dead.

Marius' consular colleague in 102 BC, Quintus Lutatius Catulus Caesar, did not fare so well. He suffered some casualties in a minor engagement up in one of the mountain valleys near Tridentum. Catulus then withdrew and the Cimbri entered northern Italy. The Cimbri paused in northern Italy to regroup and await expected reinforcements from the other Alpine passes.

Marius was reelected to his fourth consecutive consulship as consul for 101 BC with his friend Manius Aquillius as his colleague. After election, he deferred a triumph for Aquae Sextiae, and marched north with his army to join Catulus, whose command was prorogued since Marius' consular colleague was dispatched to defeat the slave revolt in Sicily. Meeting with the Cimbri, the invading tribesmen threatened the Romans with the advance of the Teutones and Ambrones. After informing the Cimbri of their allies' destruction, both sides prepared for battle.

Rome won a decisive victory in the ensuing Battle of the Raudian Field (or Vercellae). Caught off guard by Sulla's cavalry, pinned down by Catulus' infantry and flanked by Marius, the Cimbri were slaughtered and the survivors enslaved. Once again, Roman discipline overcame a larger barbarian force. Upwards of 120 thousand Cimbri were slain. The Tigurini gave up their efforts to enter Italy from the northeast and went home.

After fifteen days of thanksgiving, 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." At the same time, Marius' consular colleague, Manius Aquillius, defeated the Sicilian slave revolt in the Second Servile War. Having saved the Republic from destruction and at the height of his political powers, Marius was returned as consul for 100 BC with Lucius Valerius Flaccus; according to Plutarch, he also campaigned on behalf of his colleage so to prevent his rival Metellus Numidicus from securing a seat.

Sixth consulship

During the year of Marius's sixth consulship (100 BC), Lucius Appuleius Saturninus was tribune of the plebs for the second time and advocated reforms like those earlier put forth by the Gracchi. Saturninus, after assassinating one of his political opponents to the tribunate, pushed for bills that would: drive his former commanding officer Metellus Numidicus into exile, lower the price of wheat distributed by the state, and give colonial lands to the veterans of Marius's recent war. Saturninus' bill gave lands to all veterans of the Cimbric wars, including those of Italian allies, which was resented by some of the plebs urbana. Marius, an Italian, was always supportive of the allies' rights, generously granting citizenship for acts of valour.

The Senate and Marius, however, increasingly opposed Saturninus's measures. Eventually, Saturninus and Glaucia had an opponent, Gaius Memmius, assassinated in the middle of the voting for the consular elections for 99 BC, prompting widespread violence. Called to an emergency session by Marius, the Senate issued its 'final decree' (the Senatus consultum ultimum), and ordered Marius, as consul, to put down the revolt.

Marius, although he was generally allied with the radicals, complied with the request and put down the revolt in the interest of public order. Rallying volunteers from the urban plebs and his veterans, Marius cut the water supply to the Capitoline hill and put Saturinus' barricades under a short and decisive siege. After Saturninus and Glaucia surrendered, Marius attempted to keep Saturninus and his followers alive by locking them safely inside the Senate house, where they would await prosecution according to the law. Possibly with Marius' implied consent, an angry mob broke into the building and, by dislodging the roof tiles and throwing them at the prisoners below, lynched those inside. Glaucia too was dragged from his house and killed in the street.

In complying with the Senate's wishes, Marius tried to show the Senate, who had always been suspicious of his motives, that he was one of them instead of the outsider that Quintus Metellus said he was in 108 BC. Marius's overall concern, for his part, was always how to maintain the Senate's esteem: in the words of the scholar A.N. Sherwin-White, Marius 'wanted to end his days as vir censorius, like the other great worthies among the novi homines of the second century'.

90s BC

After the events of 100 BC, Marius at first tried to oppose the recall of Metellus Numidicus, who had been exiled by Saturninus in 103. However, seeing that opposition was impossible, Marius decided to travel to the east in 98 BC, ostensibly to fulfil a vow he had made to the goddess Bona Dea.

Plutarch portrays this voluntary exile as a great humiliation for the six-time consul: 'considered obnoxious to the nobles and to the people alike', he was even forced to abandon his candidature for the censorship of 97. Plutarch also reports that while in the East, Marius attempted to goad Mithridates VI of Pontus into declaring war on Rome, so that the Roman people might be forced to rely on Marius's military leadership once more.

However, scholars have pointed out that Marius's supposed 'humiliation' cannot have been too long-lasting. In c. 98–97 BC, he was given the unprecedented honour of being elected in absentia to the college of priestly augurs whilst away in Asia Minor. Furthermore, Marius's mere presence at the trial of Manius Aquillius in 98 BC, his friend and former colleague as consul in 101 BC, was enough to secure acquittal for the accused, even though he was apparently guilty. In 95 BC, Marius also successfully acted as sole defence for T. Matrinius, an Italian from Spoletium who had been granted Roman citizenship by Marius and who was now accused under the terms of the Lex Licinia Mucia.

Social War

While Marius was away in the east and after he returned, Rome had several years of relative peace. But in 95 BC, Rome passed a decree, the Lex Licinia Mucia, expelling from the city all residents who were not Roman citizens. In 91 BC, Marcus Livius Drusus was elected tribune and proposed a greater division of state lands, the enlargement of the Senate, and a conferral of Roman citizenship upon all freemen of Italy. But after Drusus was assassinated, many of the Italian states then revolted against Rome in the Social War of 91–88 BC, named after the Latin word for ally, socii.

Marius, rather humiliatingly, had to serve as a legate with his nephew, the consul Publius Rutilius Lupus. Lupus died in a Marsic ambush on the River Tolenus. Marius, who was leading another column of men, crossed the river at a different location and captured the Marsic camp. He then marched on the Marsi while they were busy stripping the corpses and dealt with them accordingly. With Marius in command of their camp and supplies the Marsi had to withdraw. Marius then sent the corpses of Lupus and his officers back to Rome. Following this, Marius took command of and regrouped Lupus' army. The Senate then decided to give joint command to Marius and the praetor Quintus Servilius Caepio the Younger. Marius had expected sole command and he did not get along with Caepio with disastrous results. After having dealt with a raiding legion of Marsi at Varnia Caepio attempted to give Marius instructions, but Marius ignored them. Caepio left on his own was then obliged to move his legions back towards Caeoli. Once they reached the Arno at Sublaqueum they were attacked by the Marsi. Caepio's colomn perished to the last man. It is said he was killed by Quintus Poppaedius Silo himself. Marius now in sole command continued the fight against the Marsi and their allies. After a lot of maneuvering the Marsi and Marruncini were defeated in a battle where Marius worked in tandem with Lucius Cornelius Sulla, his old subordinate from the Jugurthine and Cimbri wars, together they killed 6,000 rebels, including the Marruncini general Herius Asinus, and captured 7,000. Marius failed to follow up on this success for unknown reasons (probably because he did not trust his men's morale), he steadfastly refused to engage the enemy. This led Poppaedius Silo, one of the Marsi generals, to challenge him: 'So if you are such a great general, Marius, why not come down [from your fortifications] and fight it out?' To this Marius retorted 'Well, if you think you are any good a general, why don't you try to make me?'

By 89 BC Marius had or had been retired from the war. Either he had withdrawn under the pretext of ill-health because he felt he was being under-appreciated or he was genuinely ill. There is also the possibility that when his command lapsed at the end of 90 BC the government simply did not renew it or they may have offered him a face-saving deal: retire and claim infirmities.

The Italian war for citizenship was hard-fought. And in 90 BC, the Assembly carried a law, the lex Julia de civitate latinis et sociis danda to grant citizenship to Italians not yet under arms. In early 89 BC, with the expansion of the war slowing, the Senate dispatched Lucius Porcius Cato to take over the troops under Marius' command. Shortly after arriving, he forced Marius to resign his legateship by claiming he was in poor health.

Marius' experience in the conflict brought him few honours, though he served at a senior level and won at least a few victories. In all likelihood, this experience rekindled his desire for further commands and glory, embarking on a path towards seeking command in the east.

Sulla and the First Civil War

During the Social War, one of Marius' clients and friends, Manius Aquillius, had apparently encouraged the kingdoms of Nicomedia and Bithynia to invade Pontus. In response, King Mithridates of Pontus responded by invading both kingdoms and Roman holdings in Asia (modern day western Asia minor). Defeating the meagre forces at Aquillius' disposal, Mithridates marched across the Bosphorus and Aquillius retreated to Lesbos. With the Social War concluded and with the prospects of a glorious and fabulously rich conquest, there was significant competition in the consular elections for 88 BC. Eventually, Lucius Cornelius Sulla was elected consul and received command of the army to be sent to Pontus.

After Sulla left Rome for his army in Nola to depart for the East, Publius Sulpicius Rufus called an assembly which appointed Marius – a private citizen lacking any office in the Republic – to the command in Pontus. Upon hearing of this, Sulla rallied his troops to his personal banner and called upon them to defend him against the insults of the Marian faction. Loyal to Sulla and worried that they would be kept in Italy while Marius raised troops from his own veterans, the armies pledged their loyalty to Sulla. Marius' faction sent two tribunes to Sulla's legions in eastern Italy, who were promptly murdered by Sulla's troops.

Sulla then ordered his troops to begin a slow march on Rome. This was a momentous event, and was unforeseen by Marius, as no Roman army had ever marched upon Rome: it was forbidden by law and 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' ad-hoc force was no match for Sulla's legions. Marius was defeated and fled Rome. Marius narrowly escaped capture and death on several occasions and eventually found safety with his veterans in Africa. Sulla and his supporters in the Senate proscribed twelve men, including a death sentence passed on Marius, Sulpicius and a few other allies. A few men – including Sulpicius – were executed but, according to Plutarch, many Romans disapproved of Sulla's actions.

Some who opposed Sulla wereelected to office in 87 BC – Gnaeus Octavius, a supporter of Sulla, and Lucius Cornelius Cinna, a supporter of Marius and member of Sulla's extended family, were elected consuls – as Sulla wanted to demonstrate his republican bona fides. Regardless, Sulla was again confirmed as the commander of the campaign against Mithridates, so he took his legions out of Rome and marched east to the war.

Seventh consulship and death

While Sulla was on campaign in Greece, fighting broke out between the conservative supporters of Sulla, led by Octavius, and the popular supporters of Cinna over voting rights for the Italians. When Cinna was forced to flee the city by Octavius' gangs, he was able to rally significant Italian support: some 10 legions including the Samnites.

Marius along with his son then returned from exile in Africa to Etruria with an army he had raised there and placed themselves under consul Cinna's command to oust Octavius. Cinna's vastly superior army coerced the Senate into opening the gates of the city.

While Cinna had sworn an oath not to kill anyone, Marius and his soldiers had not. They entered Rome and started murdering the leading supporters of Sulla, including Octavius. Their heads were exhibited in the Forum. We know of fourteen victims important enough to be named, including six former consuls. Lucius Licinius Crassus (older brother of the triumvir), Gaius Atilius Serranus, Marcus Antonius Orator, Lucius Julius Caesar, his brother Caesar Strabo, Quintus Mucius Scaevola the Augur, Publius Cornelius Lentulus, Gaius Nemotorius, Gaius Baebius and Octavius Ruso. For five days, the Marian faction purged the city of its enemies before putting an end to the terror. Following the short purge, Cinna organised elections, where he permitted two people to run for consul: himself and Marius. Naturally, they were elected as consuls for 86 BC.

Plutarch relates several opinions on the end of Marius: one, from Posidonius, holds that Marius contracted pleurisy; Gaius Piso has it that Marius walked with his friends and discussed all of his accomplishments with them, adding that no intelligent man ought leave himself to fortune. Plutarch then anonymously relates that Marius, having gone into a fit of passion in which he announced in a delusionary manner that he was in command of the Mithridatic War, began to act as he would have on the field of battle; finally, Plutarch relates, that ever an ambitious man, Marius lamented, on his death bed, that he had not achieved all of which he was capable, despite his having acquired great wealth and having been chosen consul more times than any man before him.

Marius died on 13 January 86 BC, just seventeen days into his seventh consulship. Lucius Valerius Flaccus succeeded Marius as consul. Cinna would lead the Marian faction into the civil war, which continued until Sulla won control of the state and made himself dictator with an undefined term.

Marius was a highly successful Roman general and military reformer. In ancient sources, he is repeatedly characterised as having unending ambition and opportunism. Plutarch says of him:

if Marius could have been persuaded to sacrifice to the Greek Muses and Graces, he would not have put the ugliest possible crown upon a most illustrious career in field and forum, nor have been driven by the blasts of passion, ill-timed ambition, and insatiable greed upon the shore of a most cruel and savage old age.

This characterisation is not viewed by modern historians as entirely fair, for Marius' attempts to win the consulship and for self-aggrandisement were not out of the norm of politicians of the middle to late Republic. Marius' legacy is heavily defined by his example: his five successive consulships, while seen contemporaneously as necessary for the survival of Roman civilisation, gave unprecedented power into the hands of a single man over a never-before-seen length of time.

Reforms to the legions

The Marian reforms to the logistics and organisation of the Roman armies were profound, increasing the speed and agility of the military to react to foreign threats.

In the ancient narratives, his reforms to the recruitment process for the Roman legions are roundly criticised for creating a soldiery wholly loyal to their generals and beholden to their beneficence of ability to secure payment from the state. However, this development did not emerge from Marius. And it was likely initially envisioned as nothing more than a temporary measure to meet the extraordinary threats of Numidia and the Cimbrian tribes.

First, "the property qualification for army service had become nearly meaningless by 107" with exemptions from the property qualifications becoming commonplace and recurrent. Marius' recruitment reforms simply made plain what had been for some time commonplace, out of need for men or simply the expediency of calling up urban volunteers rather than conscripting farmers.

Second, the decision to call up the proletarii would not be fully felt until the time to draw down the troops. As the spoils of war became increasingly inadequate as compensation for the soldiers – the spoils of war do not guarantee a long term stream of income – it became common practice to allocate land for the foundation of veteran colonies (generally abroad). Passage of the legislation necessary to establish these colonies became an "increasingly irksome chore [dogging] the footsteps of senior politicians on their return ... from service overseas".

The Assemblies and foreign affairs

Marius' repeated use of the Assemblies to overturn the Senatorial commands had significant negative effects on the stability of the state. The Senate generally used sortition to choose generals for command posts, removing the conflict of interest between consuls. In the late 120s BC, Gaius Gracchus passed a lex Sempronia de provinciis consularibus which required that commands be assigned before the election of consuls. Evans writes of this lex Sempronia:

The legislation is generally seen as popular legislation for foiling senatorial contrivance of commands, and for reducing the political intrigue which often accompanied the selection of generals. It was also a sound administrative device which cracked down on the ambitions of senators who sought the leadership of special military ventures.

Marius' use of the Assemblies to remove Metellus from command in Numidia spelled an end for collective governance in foreign affairs. In later years, use of plebiscita became the main means by which commands were granted (or stolen) from other generals, adding to personal rivalries and diminishing the ability to govern the state. The size of the rewards gained from manipulating the Assemblies was irresistible to future generations of ambitious politicians.

The similar use of the Assemblies in an attempt to replace Sulla with Marius for the Mithridatic War was unprecedented, as never before had laws been passed to confer commands on someone lacking any official title in the state. Sulla's reaction of marching on the city proved disastrous for the Republic, leading to the normalisation of military interference in political affairs.

Political violence

While political violence had been increasingly normalised throughout the middle and late Republic, starting with the murder of the Gracchi brothers, the passage of the senatus consultum ultimum against Saturninus and Glaucia in Marius' sixth consulship normalised the use of force not only against private citizens, but also "against properly elected magistrates in order to preserve [the Senate's] own position".

Moreover, Marius' attempts to undermine Sulla's command at the start of the First Mithridatic War massively expanded the scope of that violence. No longer would only mobs clash in the streets of Rome. No longer would personal grudges solely be pursued in the courts: political enemies would be executed en masse. At a broad level, the use of the Assemblies totally eroded senatorial control and created significant and prolonged instability, only resolved by the destruction of the Republican form of government and the transition to Empire.

The historical novels The First Man in Rome and The Grass Crown, by Colleen McCullough, largely focus on the rise and fall of Gaius Marius and his lengthy career.

The short story "Marius", by American science fiction author Poul Anderson, uses the historical Marius, and the destructive effects of his acts on the long-term viability of the Roman Republic, to illuminate the motivation of the protagonist in a conflict in post-World War III Europe.

The poems Marius Amongst the Ruins of Carthage by Felicia Hemans (in The Edinburgh Magazine, 1821) and Marius at the Ruins of Carthage by Letitia Elizabeth Landon (in The Keepsake, 1833) both dwell on his state of exile there and his still rebellious spirit.