Gaius Marius: the man who remade Rome's army

Gaius Marius came from a country town, had no famous ancestors and never learned Greek, yet he was consul seven times, more than any Roman before him. He ended the war against Jugurtha, destroyed two migrating peoples who had beaten Roman army after Roman army, and was hailed as the third founder of Rome. Then he turned his ambition on the Republic itself, and his feud with his former officer Sulla opened the age of civil wars.¹

Early life

Marius was born about 157 BC near Arpinum in Latium, in a village that Britannica calls Cereatae and Plutarch's text gives as Cirrhaeaton. His family were of equestrian rank, the class below the senators, and he grew up in country ways. Plutarch says he never studied Greek literature, thinking it absurd to learn from teachers who were the subjects of another people; Britannica notes that he lacked the Greek education normal for the upper classes.²

His first campaign was in Spain, on the staff of Scipio Aemilianus at the siege of Numantia in 134 BC. There he caught his general's eye by his courage and by the cheerful way he accepted Scipio's hard new discipline. The young Numidian prince Jugurtha served in the same army and also impressed Scipio.³

A new man in politics, 119 to 108 BC

With the backing of the powerful Caecilii Metelli he was elected tribune of the plebs for 119 BC and passed a law on voting procedure that cut the nobles' influence over voters, threatening a consul with prison when the Senate tried to stop it. He was then only just elected praetor for 115, accused of bribery and acquitted, and governed Further Spain, where he cleared out bandits and, Britannica adds, made a fortune from mining investments.⁴

He married well. His wife Julia came from the patrician Julii Caesares and was the aunt of Julius Caesar, who, Plutarch says, took Marius as a model.⁵

The war against Jugurtha, 107 to 105 BC

When Quintus Metellus took the command against Jugurtha, now king of Numidia, Marius went with him as an officer. Metellus beat Jugurtha in open battle but could not end the guerrilla war that followed. Marius returned to Rome, blamed his commander for the delay, and was elected consul for 107 BC, a novus homo or new man without consular ancestors. A popular vote handed him the African command over the head of the furious Metellus.⁶

To raise fresh troops he broke with custom. Sallust, who wrote the history of this war, says he enrolled soldiers "not according to the classes in the manner of our forefathers", but taking any volunteer, most of them from the poorest citizens, the capite censi who were counted only by head. Britannica explains the change by a shortage of men qualified by property, who alone had been liable for service.⁷

In Africa Marius kept Jugurtha on the run but, like Metellus, could not catch him. The war ended by betrayal. In 105 BC King Bocchus of Mauretania, Jugurtha's father-in-law, handed him over in chains, not to Marius himself but to his quaestor Lucius Cornelius Sulla. Sulla had the scene engraved on his signet ring, and the quarrel over who deserved the credit, Plutarch and Britannica agree, was the seed of a lifelong feud.⁸

On 1 January 104 BC, the day he took up his second consulship, Marius celebrated his triumph, with Jugurtha walking before his chariot; the king was then put to death in prison. Livy's summary adds that Marius entered the Senate in his triumphal robes, which no one had done before.⁹

The Cimbri and Teutones, 104 to 101 BC

Rome needed him. The Cimbri and Teutones, migrating peoples from the north, had defeated one Roman army after another, and in 105 BC two armies were destroyed near Arausio, the modern Orange, in a disaster that Livy's summary, quoting the annalist Valerius Antias, puts at 80,000 soldiers and 40,000 servants killed. Marius was elected consul again for 104, and the voters re-elected him every year until 100, five consulships in a row.¹⁰

He used the time the barbarians gave him to train his army. Plutarch writes that he practised the men in running and long marches and made them carry their own baggage and prepare their own food, so that hard-working, uncomplaining soldiers were later called "Marian mules". While he waited for the enemy in southern Gaul, his men dug a canal at the mouth of the Rhône, the Fossa Mariana, which still bore his name in Plutarch's day.¹¹

In 102 BC the Teutones and Ambrones marched along the coast toward Italy, and Marius destroyed them in two battles near Aquae Sextiae, modern Aix-en-Provence. The Cimbri had meanwhile crossed the Alps and driven back the consul Quintus Lutatius Catulus; in 101 BC Marius joined Catulus and together they crushed the Cimbri near Vercellae in northern Italy, a site Britannica places near modern Rovigo in the Po valley. The ancient figures are huge and disagree: Plutarch says more than 100,000 were killed or taken at Aquae Sextiae, while Livy's summary gives 200,000 killed and 90,000 captured; for Vercellae, Plutarch gives more than 60,000 prisoners and twice that number dead, Livy 160,000 killed and 60,000 captured.¹²

This was the summit of his career. Plutarch writes that the people hailed him as the third founder of Rome, for the danger he had averted was no less than the Gallic invasion of old, and offered libations to him at home alongside the gods. But the joint triumph with Catulus left bad blood, for Marius claimed the whole credit; Sulla, who fought in the battle, and Catulus himself later accused him of arranging his line so that his own men would win all the glory.¹³

The army reforms: what we know

Later historians grouped Marius's measures under the name of the Marian reforms. Britannica credits him, besides the new recruitment, with making the legionary eagle the standard of every legion and with tactical changes that made the cohort the main unit, and argues that the result was a professional army more loyal to its general than to the state. Michał Norbert Faszcza, in a 2021 study in the journal Res Historica, argues the opposite: no ancient author mentions any reform carried out by Marius, and the picture of a single program grew out of a few ancient passages read creatively by 19th-century scholars and repeated until it became dogma.¹⁴

What both camps accept is what Sallust and Plutarch record: in 107 BC Marius opened the legions to volunteers without property, and he trained his army to march far, carry its own load and fight hard.¹⁵

Command style

Britannica describes him as a strong, brave soldier and a skillful general who was popular with his troops but showed little flair for politics and was a poor public speaker. Plutarch's portrait is of a man trained in camps rather than in the city, hardy and temperate, but fierce in authority and consumed by ambition. Both agree that his strength lay in the field, with soldiers who trusted him, and his weakness in the Forum.¹⁶

Later life and death

Politics went badly. In 100 BC, consul for the sixth time, he allied himself with the radical tribune Saturninus, then turned against him when the Senate called on the consuls to save the state; Saturninus and the praetor Glaucia were killed, and Marius, says Britannica, was smeared as a man who betrayed his friends as well as his enemies. He left for the East, where he met Mithridates VI of Pontus, and in the Social War of 90 to 88 BC against Rome's Italian allies he was, in Britannica's words, beginning to show his age; Plutarch, who says he was past 66, describes him as slow and hesitant, though he still won a victory in which 6,000 of the enemy fell.¹⁷

In 88 BC the tribune Sulpicius passed a law transferring the command against Mithridates from the consul Sulla to the old general. Sulla marched his army on Rome, and Marius fled. Plutarch tells the famous stories of the flight: Marius hiding in a marsh near Minturnae, a Gallic or Cimbrian horseman sent to kill him who fled crying that he could not kill Gaius Marius, and Marius in Africa sending back the governor's messenger with the words: "Tell him, then, that thou hast seen Caius Marius a fugitive, seated amid the ruins of Carthage." Britannica warns that these near-catastrophes were much embroidered in the telling.¹⁸

In 87 BC, while Sulla fought in Greece, Marius landed in Etruria, raised an army, sacked Ostia and with the consul Cinna took Rome. Both were elected consuls for 86, Marius for the seventh time, and a massacre of their enemies followed, Catulus among them. Marius died in January 86 BC, at about seventy: Britannica dates his death to 13 January, while Plutarch says he died seventeen days after taking up his seventh consulship on the first day of the year.¹⁹

Legacy and memory

Britannica sees Marius as the first Roman to show how much political support a successful general could draw from the votes of his veterans, a lesson that Sulla, Caesar and Octavian learned and used with overwhelming effect. When Julia died, her nephew Julius Caesar praised her in a public funeral speech and dared to carry images of Marius in the procession, the first time they had been seen since Sulla's rule.²⁰

See how his soldiers fought in how the Roman legion worked, read the life of his nephew by marriage Julius Caesar, or explore the other great commanders of ancient Rome.