Attila the Hun in the context of "Orestes (father of Romulus Augustulus)"

The first millennium of the anno Domini or Common Era was a millennium spanning the years 1 to 1000 (1st to 10th centuries; in astronomy: JD 1721425.5 – 2086667.5). The world population rose more slowly than during the preceding millennium, from about 200 million in the year 1 to about 300 million in the year 1000.

In Western Eurasia (Europe and Near East), the first millennium was a time of great transition from Classical Antiquity to the Middle Ages. The 1st century saw the peak of the Roman Empire, followed by its gradual decline during the period of Late Antiquity, the rise of Christianity and the Great Migrations. The second half of the millennium is characterized as the Early Middle Ages in Europe, and marked by the Viking expansion in the west, and the continuation of the Byzantine Empire (Eastern Roman Empire) in the east.

Hungary in its modern (post-1946) borders roughly corresponds to the Great Hungarian Plain (the Carpathian Basin) in Central Europe.

During the Iron Age, it was located at the crossroads between the cultural spheres of Scythian tribes (such as Agathyrsi, Cimmerians), the Celtic tribes (such as the Scordisci, Boii and Veneti), Dalmatian tribes (such as the Dalmatae, Histri and Liburni) and the Germanic tribes (such as the Lugii, Marcomanni). In 44 BC, the Sarmatians, Iazyges moved into the Great Hungarian Plain. In 8 AD, the western part of the territory (the so-called Transdanubia) of modern Hungary formed part of Pannonia, a province of the Roman Empire. Roman control collapsed with the Hunnic invasions of 370–410, the Huns created a significant empire based in present-day Hungary. In 453 they reached the height of their expansion under Attila the Hun. After the death of Attila, the empire collapsed in 455, and Pannonia became part of the Ostrogothic Kingdom. The western part of the Carpathian Basin was occupied by the Longobards and the eastern part by the Gepids. In 567, the Avars occupied the territory ruled by the Gepids. In 568, the Longobards moved to Italy from Transdanubia, and the Avars also occupied that territory, Khagan Bayan I established the Avar Khaganate. The Avars were defeated by the Franks and Bulgars, and their steppe-empire ended around 822.

The term Nibelung (German) or Niflungr (Old Norse) is a personal or clan name with several competing and contradictory uses in Germanic heroic legend. It has an unclear etymology, but is often connected to the root Nebel, meaning mist. The term in its various meanings gives its name to the Middle High German heroic epic the Nibelungenlied.

The most widespread use of Nibelung is used to denote the Burgundian royal house, also known as the Gibichungs (German) or Gjúkingar (Old Norse). A group of royal brothers led by king Gunther or Gunnar, the Gibichungs are responsible for the death of the hero Siegfried or Sigurd and are later destroyed at the court of Attila the Hun (called Etzel in German and Atli in Old Norse). This is the only use of the term attested in the Old Norse legends.

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.

Theodoric I (Gothic: Þiudarīks; Latin: Theodericus; c. 390 or 393 – 20 or 24 June 451) was the king of the Visigoths from 418 to 451. Theodoric is famous for his part in stopping Attila the Hun at the Battle of the Catalaunian Plains in 451, where he was killed.

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.