Marius was of humble beginnings, having been born near the town of Arpinum in Latium.
First serving in Spain, Marius was essentially a military man. He did not hold any public office until he was voted to the position of Tribune of the People in 119 BC.
In 115 BC he became praetor and married Julia, of the powerful patrician family of the Julii. This marriage should in effect make him the uncle of Julius Caesar.
Next he served in Africa in the wars against Jughurta. The commander of the Roman forces, Metellus, was not very successful against teh foe, and so in 108 BC Marius returned to Rome and stood for the office of consul. He won the election, but now used his standing to persuade the comitia tributa so elect him the new commander of the forces in Africa.
This was unlawful and showed how little the grizzled military man, which Marius was, thought of following proper procedures. For only the senate had authority to appoint military commanders.
To raise new forces with which to set over to Africa, Marius now broke yet another tradition. Rather than to enlist from the landowning classes, Marius now offered the soldier's job to Rome's poor, promising them adventure, glory and booty. But most of all he offered them jobs, a means of making a living.
Perhaps unwittingly Marius set in motion a revolution in Roman army affairs, and his action is a landmark in Roman history.
This new, professional army, trained by new methods introduced by Marius, set over to Africa and made easy work of bringing the war to an end. Although the eventual negotiations had most of the glory slip from Marius' grasp, as it was a young quaestor, Cornelius Sulla, who should achieve victory and peace in these talks, not Marius.
At about this point in time (105 BC) a disaster befell the Romans on their northern borders. Under the command of Caepio and Manlius, they suffered a crushing defeat against the barbarians at Arausio.
It was teh worst setback the Romans had suffered since the awful defeat by Hannibal at Cannae.
Had Marius and his new army of mercenaries crushed Jughurta, then now Rome laid its trust in him to save them from the menace which lay to the north.
Marius, elected consul again in 105 BC, enojyed successive election victories as consul until 101 BC, during which time his task was to destroy the menace of the Cimbri and Teutones, who had shattered teh Romans earlier.
He did so in two great battles, annihilating the Teutones 102 BC at Aquae Sextiae and in 101 BC the Cimbri at Campi Raudii near Vercellae.
With Rome safe from northern invaders, Marius now sought to repay the debt to his army by establishing laws by which veterans should receive land after having served their time.
For this he allied himself with the Tribune of the People Lucius Appuleius Saturninus. Saturninus was a ruthless figure not beyond using violence for political means. This political alliance managed to win Marius yet another consulship in 100 BC. In the same year Saturninus brought forward on Marius' behalf proposals by which soldiers should be allotted land on discharge form the army. Also part of the bill was the granting of Roman citizenship to Italian allies who had contributed ther fair share in the defeat of the barbarians.
The proposals were eventually accepted, but not without determined opposition and the outbreak of violence in the streets of Rome. Marius had to call his soldiers into to Rome to restore order. But of course the arrival of the troops was not merely a question of keeping the peace. It was an implied threat as to what might happen if veterans should be denied land.
Once more Marius created a precedent of historic proportions. For it was the first time in which it emerged that no-one could rule Rome without the support of the army.
Saturninus now however should finally stumble, when he organised the assassination of a political opponent. This was a step too far and the senate issued a senatus consultum ultimum, order of highest authority known to the Roman constitution, ordering Marius to take action against Saturninus. Marius had no choice but to oblige, arresting his chief political ally. But Saturninus was doomed. A enraged mob broke into his cell and lynched him.
Worse still for Marius, the senate no declared all of Saturninus' laws nill and void, on the basis that they had been achieved only by force.
Marius was ruined. Once his consulship came to an end (and he became legally liable for his former deeds) he fled into exile. But he was not finished.
The Social War (91-89 BC), which saw much of Italy in chaos, saw his return as an active commander.
Next in 88 BC Mithridates, King of Pontus, attacked the Roman province of Asia, where a alleged 80'000 Romans and Italians were massacred. The senate decided on the current consul, Sulla, as commander of the army against Mithridates.
But the Tribune of the People Suplicus Rufus called for the command to be given to Marius. The concilium plebis backed this proposal. But Sulla proved a man not to be messed with. He marched on Rome at the head of six legions and forced the reversal of this decision.
Had Marius once called his troops to put down street violence, then this was the first time any Roman commander had ever used troops against Rome. The Tribune Sulpicus went fell victim to Sulla's wrath and was killed.
The seventy year old Marius fled, but was arrested somewhere along the coast of Latium. He was sentenced to death, but no was willing to execute the old man. And so he was instead put on a ship to Africa. Ending up in Carthage he was deemed a risk too hot to handle and the provincial governor demadned that he moved on.
Exiled a second time, Marius' story still was not at an end.
While Sulla was in Asia, fighting Mithridates, the consul Cornelius Cinna tried introduce legislation by which Italians who had recetly received Roman citizenship would be enrolled into the city's so called tribes.
After his proposals caused a political rumpus in Rome, Cinna was thrown out of the city by his fellow consul. Though Cinna would not accept defeat and raised an army of Italians in very short time. This was the moment which saw Marius' near miraculous return to Italy at the head of a small cavalry force (87 BC).
In his bid to increase the numbers of his force, Marius didn't refrain from freeing farm slaves by force and adding them to his ranks.
At the head of this ramshackle force Marius and Cinna now closed on Rome and besieged the capital. Thousands perished in the siege. The government alas surrendered, once they had received Cinna's promise that thereafter there should be no more killing.
Marius however had promised no such thing. No sooner had the gates been opened the slaughter began, lasting for five gruelling days.
The next year, 86 BC, saw Marius and Cinna reestablished as consuls. But Marius was not to enjoy the glory for long. He died on 13 January, most likely of old age.
His legacy to Rome was enormous. Marius had made his mark in Roman history by reforming the army. He had achieved the office of consul no fewer than seven times. And yet he also destabilized Rome for years to come and raped her in a gruesome siege and a five day massacre.