Foederati in the context of "Socii"

The Visigoths (/ˈvɪzɪɡɒθs/; Latin: Visigothi, Wisigothi, Vesi, Visi, Wesi, Wisi) were a Gothic people who emerged in the Balkans during late antiquity. Likely descended from the Thervingi who entered the Roman Empire in 376 and defeated the Romans at the Battle of Adrianople (378), they were first united under Alaric I (395–410), whose forces alternately fought and allied with Rome before famously sacking the city in 410.

In 418, the Visigoths were settled as foederati in southern Gaul, establishing a kingdom with its capital at Toulouse. From there they expanded into Hispania, displacing the Suebi and Vandals. Defeat by the Franks under Clovis I at the Battle of Vouillé (507) ended Visigothic rule in Gaul, but the kingdom consolidated in Spain and Portugal, where it endured for two centuries.

The Crisis of the Third Century, also known as the Military Anarchy or the Imperial Crisis, was a period in Roman history during which the Roman Empire nearly collapsed under the combined pressure of repeated foreign invasions, civil wars and economic disintegration. At the height of the crisis, the Roman state split into three distinct and competing polities. The period is usually dated between the death of Severus Alexander (235) and accession of Diocletian (284).

The crisis began in 235 with the assassination of Emperor Severus Alexander by his own troops. During the following years, the empire saw barbarian invasions and migrations into Roman territory, civil wars, peasant rebellions and political instability, with multiple usurpers competing for power. This led to the debasement of currency and a breakdown in both trade networks and economic productivity, with the Plague of Cyprian contributing to the disorder. Roman armies became more reliant over time on the growing influence of the barbarian mercenaries known as foederati. Roman commanders in the field, although nominally loyal to the state, became increasingly independent of Rome's central authority.

The Burgundians (Latin: Burgundiones or less commonly Burgundii) were a Germanic people of the Roman imperial era, who established the powerful Kingdom of the Burgundians within the Roman empire, in what is now western Switzerland and south-eastern France. This kingdom is the source of much later names related to the region of Burgundy, including medieval entities such as the Duchy of Burgundy.

In earlier periods, peoples with the same name were reported by Roman sources to have lived in different parts of what is now Germany and Poland, and there are believed to be connections between at least some of these groups. For one thing, the kingdom's core group were followers of the Gibichung dynasty, who had previously led them as foederati in Roman territory on the Rhine border, probably near Worms in present day Germany. They left the Rhine after the Romans and their Hun allies killed many of the Burgundians along with their king Gundahar in 436, accusing them of rebellion. The death of Gundahar at the hands of the Huns became a central theme in medieval Germanic heroic legend, including the Nibelungenlied (where he is “Günther”) and the Völsunga saga (where he is “Gunnar”). After the remnants resettled in Sapaudia near Lake Geneva in about 443, their territory expanded to include Lyon as a new capital. The entire kingdom was incorporated into the Frankish empire in 534.

The Ostrogothic Kingdom, officially the Kingdom of Italy (Latin: Regnum Italiae), was a barbarian kingdom established by the Germanic Ostrogoths that controlled Italy and neighbouring areas between 493 and 553. Led by Theodoric the Great, the Ostrogoths killed Odoacer, a Germanic soldier and erstwhile leader of the foederati. Odoacer had previously become the de facto ruler of Italy following his deposition of Romulus Augustulus, the final emperor of the Western Roman Empire, in 476. Under Theodoric, the Ostrogothic kingdom reached its zenith, stretching from Southern France in the west to Western Serbia in the southeast. Most of the social institutions of the late Western Roman Empire were preserved during his rule. Theodoric called himself "King of the Goths and Romans" (Latin: Gothorum Romanorumque Rex), demonstrating his desire to be a leader for both peoples.

Under Justinian I, the Byzantine Empire embarked on a campaign to reconquer Italy in 535. Witiges, who was the Ostrogothic ruler at that time, could not defend the kingdom successfully and was finally captured when the capital Ravenna fell. The Ostrogoths rallied around a new leader, Totila, and largely managed to reverse the conquest, but were eventually defeated. The last king of the Ostrogothic Kingdom was Teia.

The Visigothic Kingdom, Visigothic Spain or Kingdom of the Goths (Latin: Regnum Gothorum) was a barbarian kingdom that occupied what is now southwestern France and the Iberian Peninsula from the 5th to the 8th century. One of the Germanic successor states to the Western Roman Empire, it was originally created by the settlement of the Visigoths under King Wallia in the province of Gallia Aquitania in southwest Gaul by the Roman government and then extended by conquest over all of Hispania. The Kingdom maintained independence from the Eastern Roman or Byzantine Empire, whose attempts to re-establish Roman authority in Hispania were only partially successful and short-lived.

The Visigoths were romanized central Europeans who had moved west from the Danube Valley. They became foederati of Rome, and sought to restore the Roman order against the hordes of Vandals, Alans and Suebi. The Western Roman Empire fell in 476 AD; therefore, the Visigoths believed they had the right to take the territories that Rome had promised in Hispania in exchange for restoring the Roman order. Under King Euric—who eliminated the status of foederati—a triumphal advance of the Visigoths began. Alarmed at Visigoth expansion from Aquitania after victory over the Gallo-Roman and Breton armies at Déols in 469, Western Emperor Anthemius sent a fresh army across the Alps against Euric, who was besieging Arles. The Roman army was crushed at the nearby Battle of Arles, resulting in Euric capturing Arles and secured much of southern Gaul.

The Battle of the Catalaunian Plains (or Fields), also called the Battle of the Campus Mauriacus, Battle of Châlons, Battle of Troyes or the Battle of Maurica, took place on 20 June 451 AD, between a coalition, led by the Roman general Flavius Aetius and the Visigothic king Theodoric I, against the Huns and their vassals, commanded by their king, Attila. It proved to be one of the last major military operations of the Western Roman Empire, although Germanic foederati composed the majority of the coalition army. The exact strategic significance is disputed. Historians generally agree that the siege of Aurelianum was the decisive moment in the campaign and stopped the Huns' attempt to advance any further into Roman territory or establish vassals in Roman Gaul. However, the Huns looted and pillaged much of Gaul and crippled the military capacity of the Romans and Visigoths. Attila died only two years later, in 453. After the Battle of Nedao in 454, the coalition of the Huns and the incorporated Germanic vassals gradually disintegrated.