Flavius Aetius in the context of "Merovech"

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.

The Kingdom of the Burgundians, or First Kingdom of Burgundy, was one of the so called "barbarian kingdoms" of the late Western Roman Empire in the fifth and sixth centuries. It began in what is now western Switzerland and southeastern France, and was ruled by Burgundian kings who were successors of the older House of Gibichung, but also held office as Roman military officers. In 451, the Burgundians helped the Roman-led allies defeat Attila at the Battle of the Catalaunian Plains, and in 455, they helped Roman-mandated forces led by Theodoric II, king of the Visigothic Kingdom, to defeat the Kingdom of the Suebi. After this, the Burgundians were able to expand their territories and their role in the Roman empire, and they moved their capital from Geneva to Lyon. In 534, the rule of the Burgundian kings ended and the kingdom became part of Francia.

The kingdom grew out of the 443 Imperial Roman resettlement of allied Burgundians to the region of Sapaudia, which at that time included Lake Geneva. These Burgundians were built around the remnants of a previous Roman-allied Burgundian kingdom which the Romans had allowed to settle on the western bank of their Rhine border at Borbetomagus, probably near Worms, having previously been Roman allies living east of the Rhine, outside the empire. The tribal ruler who was responsible for this move was Gundahar. In about 436, Gundahar and many of the people he led were killed by the Roman military leader Flavius Aetius working with his Hun allies.

Gundaharius or Gundahar (died 437), better known by his legendary names Gunther (Middle High German: Gunther) or Gunnar (Old Norse: Gunnarr), was a historical King of the Burgundians in the early 5th century. Gundahar is attested as ruling his people shortly after they crossed the Rhine into Roman Gaul. He was involved in the campaigns of the failed Roman usurper Jovinus before the latter's defeat, after which he was settled on the left bank of the Rhine as a Roman ally. In 436, Gundahar launched an attack from his kingdom on the Roman province of Belgica Prima. He was defeated by the Roman general Flavius Aetius, who destroyed Gundahar's kingdom with the help of Hunnish mercenaries the following year, resulting in Gundahar's death.

The historical Gundahar's death became the basis for a tradition in Germanic heroic legend in which the legendary Gunther met his death at the court of Attila the Hun (Etzel/Atli). The character also became attached to other legends: most notably he is associated with Siegfried/Sigurd and Brunhild, and is implicated in Sigurd's murder. He also appears as an adversary in the legend of Walter of Aquitaine. It is generally assumed that Gunther's involvement in these other legends, in which he plays a secondary or antagonistic role, is a later development. Gunther's importance in the story of the destruction of the Burgundians also waned with time.

Valentinian III (Latin: Placidus Valentinianus; 2 July 419 – 16 March 455) was Roman emperor in the West from 425 to 455. Starting in childhood, his reign over the Roman Empire was one of the longest, but was dominated by civil wars among powerful generals and the barbarian invasions. He was the youngest sole emperor in the Western Roman Empire (aged 6).

He was the son of Galla Placidia and Constantius III, and as the great-grandson of Valentinian I (r. 364–375) he was the last emperor of the Valentinianic dynasty. As a grandson of Theodosius I (r. 379–395), Valentinian was also a member of the Theodosian dynasty, to which his wife, Licinia Eudoxia, also belonged. A year before assuming the rank of augustus, Valentinian was given the imperial rank of caesar by his half-cousin and co-emperor Theodosius II (r. 402–450). The augusta Galla Placidia had great influence during her son's rule, as did the military commander Flavius Aetius, who defended the western empire against Germanic and Hunnic invasions. Attila the Hun repeatedly menaced Valentinian's domains, being repulsed by a coalition under Aetius's leadership at the Battle of the Catalaunian Plains and calling off a subsequent invasion after negotiations led by Pope Leo I.

Bucellarii (the Latin plural of Bucellarius; literally "biscuit–eater", Greek: Βουκελλάριοι) were formations of escort troops used in the Roman Empire in Late Antiquity. They were employed by high-ranking military figures (such as Flavius Aetius and Belisarius) or civil office-holders. Their name is derived from the type of bread rations eaten by these troops, so-called buccellatum. The term bucellarii came into common use during the reign of Emperor Honorius (r. 395–423).

According to Jon Coulston, one bucellarii regiment is attested in the Notitia Dignitatum. The creation of the bucellarii reflected an increase in the "use of armed retinues by public officials" in the Roman Empire. These armies were, therefore, associated with the decline of imperial authority because they demonstrated that it no longer had the monopoly of violence. The bucellarius had close ties with its commander, supporting him in his quarrel with other commanders and even against the Empire, court, and emperor. This is shown by the army of Heraclian, which was used in his attempt to seize Roman Italy from Emperor Honorius.