Cimbri in the context of "Quintus Lutatius Catulus"

Gaul (Latin: Gallia) was a region of Western Europe first clearly described by the Romans, encompassing present-day France, Belgium, Luxembourg, and parts of Switzerland, the Netherlands, Germany, and Northern Italy. It covered an area of 494,000 km (191,000 sq mi). According to Julius Caesar, who took control of the region on behalf of the Roman Republic, Gaul was divided into three parts: Gallia Celtica, Belgica, and Aquitania. Archaeologically, the Gauls were bearers of the La Tène culture during the 5th to 1st centuries BC. This material culture was found throughout Gaul and as far east as modern-day southern Poland, Slovakia, and Hungary.

Warbands led by the Gaul Brennos sacked Rome in 387 BC, becoming the only time Rome was conquered by a foreign enemy in 800 years. However, Gallia Cisalpina was conquered by the Romans in 204 BC and Gallia Narbonensis in 123 BC. Gaul was invaded after 120 BC by the Cimbri and the Teutons, who were in turn defeated by the Romans by 103 BC. Julius Caesar finally subdued the largest part of Gaul in his campaigns from 58 to 51 BC. Roman control of Gaul lasted for five centuries, until the last Roman rump state, the Domain of Soissons, fell to the Franks in AD 486.

Gaius Marius (Latin: [ˈɡaːiʊs ˈmariʊs]; c. 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. Rising from a family of smallholders in a village called Ceraetae in the district of Arpinum, Marius acquired his initial military experience serving with Scipio Aemilianus at the Siege of Numantia in 134 BC. He won election as tribune of the plebs in 119 BC and passed a law limiting aristocratic interference in elections. Barely elected praetor in 115 BC, he next became the governor of Further Spain where he campaigned against bandits.

Marius attained his first consulship in 107 BC and became the commander of Roman forces in Numidia, where he brought an end to the Jugurthine War. By 105 BC Rome faced an invasion by the Cimbri and Teutones, and the comitia centuriata elected Marius consul for a second time to face this new threat. Marius was consul every year from 104 to 100 BC, and he defeated the Teutones at Aquae Sextiae and the Cimbri at Vercellae. However, Marius suffered political setbacks during his sixth consulship in 100 BC and afterwards entered a period of semi-retirement from public life.

The Cimbrian or Cimbric War (113–101 BC) was fought between the Roman Republic and the Germanic and Celtic tribes of the Cimbri and the Teutons, Ambrones and Tigurini, who migrated from the Jutland peninsula into Roman-controlled territory, and clashed with Rome and her allies. The Cimbrian War was the first time since the Second Punic War that Italia and Rome itself had been seriously threatened.It was the first of many confrontations with Germanic tribes in Roman history that would last for centuries.

The timing of the war had a great effect on the internal politics of Rome, and the organization of its military. The war contributed greatly to the political career of Gaius Marius, whose consulships and political conflicts challenged many of the Roman Republic's political institutions and customs of the time. The Cimbrian threat, along with the Jugurthine War, allegedly inspired the putative Marian reforms of the Roman legions, a view now contested by modern historians.

The Teutons (Latin: Teutones, Teutoni; Ancient Greek: Τεύτονες) were an ancient northern European tribe mentioned by Roman authors. The Teutons are best known for their participation, together with the Cimbri and other groups, in the Cimbrian War with the Roman Republic in the late second century BC.

Some generations later, Julius Caesar compared them to the Germanic peoples of his own time, and used this term for all northern peoples located east of the Rhine. Later Roman authors followed his identification. However, there is no direct evidence about whether they spoke a Germanic language. Evidence such as the tribal name, and the names of their rulers, as they were written up by Roman historians, indicates a strong influence from Celtic languages. On the other hand, the indications that classical authors gave about the homeland of the Teutones is considered by many scholars to show that they lived in an area associated with early Germanic languages, and not in an area associated with Celtic languages.

The Battle of Vercellae or Battle of the Raudine Plain was fought on 30 July 101 BC on a plain near Vercellae in Gallia Cisalpina (modern-day Northern Italy). A Celtic-Germanic confederation under the command of the Cimbric king Boiorix was defeated by a Roman army under the joint command of the consul Gaius Marius and the proconsul Quintus Lutatius Catulus. The battle marked the end of the Germanic threat to the Roman Republic.

The Ambrones (Ancient Greek: Ἄμβρωνες) were an ancient tribe mentioned by Roman authors. They are believed by some to have been a Germanic tribe from Jutland; the Romans were not clear about their exact origin.

In the late 2nd century BC, along with the Cimbri and Teutons, the Ambrones migrated from their original homes and invaded the Roman Republic, winning a spectacular victory at the Battle of Arausio in 105 BC. The Ambrones and the Teutons, led by Teutobod, were eventually defeated at the Battle of Aquae Sextiae in 102 BC.

The Battle of Arausio took place on 6 October 105 BC, at a site between the town of Arausio, now Orange, Vaucluse, and the Rhône river, where two Roman armies, commanded by proconsul Quintus Servilius Caepio and consul Gnaeus Mallius Maximus, were heavily defeated after clashing with the migratory tribes of the Cimbri under Boiorix and the Teutons under Teutobod.

Differences between the Roman commanders prevented regular coordination between their armies, resulting in annihilation by the united Cimbrian-Teutonic force. Roman losses are thought to have been up to 80,000 legionaries in addition to 40,000 auxiliary troops. Total losses numbered up to 120,000 soldiers, the entirety of both armies. In terms of losses, this battle is regarded as the worst defeat in the history of ancient Rome, surpassing the Battle of Cannae. As a direct result of the catastrophe, the Roman military was restructured under Gaius Marius via putative reforms to the organisation and recruitment of Roman legions, which would remain principally intact for centuries thereafter. Some historians contest the existence of sudden reforms under Marius.