Attila in the context of "Gepids"

The Franks (Latin: Franci or gens Francorum; German: Franken; French: Francs) were originally a group of Germanic peoples who lived near the Rhine-river military border of Germania Inferior, which was the most northerly province of the Roman Empire in continental Europe. These Frankish tribes lived for centuries under varying degrees of Roman hegemony and influence, but after the collapse of Roman institutions in western Europe, they took control of a large empire including areas that had been ruled by Rome, and what it meant to be a Frank began to evolve. Once they were deeply established in Gaul, the Franks became a multilingual, Catholic Christian people, who subsequently came to rule over several other post-Roman kingdoms both inside and outside the old empire. In a broader sense, much of the population of western Europe could eventually be described as Franks in some contexts.

The term "Frank" itself first appeared in the 3rd century AD, during the crisis of the 3rd century – a period when Rome lost control of regions near the lower Rhine. In the 4th century, Roman authors also began to use another new collective term for enemy tribes in the lower Rhine, "Saxons". Although the Saxons and Franks were later more clearly distinguished, there are signs that the terms Frank and Saxon were not always mutually exclusive at first. Over centuries, the Romans recruited large numbers of Frankish soldiers, some of whom achieved high imperial rank. Already in the 4th century, Franks were living semi-independently in parts of Germania Inferior. The Roman administration of Britain and northern Gaul once again began to break down, and in about 406 it was the Franks who attempted to defend the Roman border when it was crossed by Alans and Vandals from eastern Europe. Frankish kings subsequently divided up Germania Inferior between them, and at least one, Chlodio, also began to rule more Romanized populations to the south, in what is now northern France. In 451, Frankish groups participated on both sides in the Battle of the Catalaunian Plains, where Attila and his allies were defeated by a Roman-led alliance of various peoples established in Gaul.

The Huns were a nomadic people who lived in Central Asia, the Caucasus, and Eastern Europe between the 4th and 6th centuries AD. According to European tradition, they were first reported living east of the Volga River, in an area that was part of Scythia at the time. By 370 AD, the Huns had arrived on the Volga, causing the westwards movement of Goths and Alans. By 430, they had established a vast, but short-lived, empire on the Danubian frontier of the Roman empire in Europe. Either under Hunnic hegemony, or fleeing from it, several central and eastern European peoples established kingdoms in the region, including not only Goths and Alans, but also Vandals, Gepids, Heruli, Suebians and Rugians.

The Huns, especially under their King Attila, made frequent and devastating raids into the Eastern Roman Empire. In 451, they invaded the Western Roman province of Gaul, where they fought a combined army of Romans and Visigoths at the Battle of the Catalaunian Fields, and in 452, they invaded Italy. After the death of Attila in 453, the Huns ceased to be a major threat to Rome and lost much of their empire following the Battle of Nedao (c. 454). Descendants of the Huns, or successors with similar names, are recorded by neighboring populations to the south, east, and west as having occupied parts of Eastern Europe and Central Asia from about the 4th to 6th centuries. Variants of the Hun name are recorded in the Caucasus until the early 8th century.

The Ostrogoths (Latin: Ostrogothi, Austrogothi) were a Roman-era Germanic people who, in the 5th and 6th centuries, established one of the two major Gothic kingdoms within the Western Roman Empire. They drew on large Gothic populations settled in the Balkans since the 4th century and rose to prominence under Theodoric the Great, who in 493 founded the Ostrogothic Kingdom in Italy after defeating Odoacer.

Theodoric belonged to the Amal dynasty, which had gained power in Pannonia after the collapse of Attila’s Hunnic empire. Backed by the Byzantine emperor Zeno, Theodoric invaded Italy and established his rule from Ravenna, preserving Roman administration, law, and culture while governing Goths and Romans under parallel systems. His reign marked the height of Ostrogothic power and stability in Italy.

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 Rugii, Rogi or Rugians (Ancient Greek: Ρογοί, romanized: Rogoi), were one of the smaller Germanic peoples of Late Antiquity who are best known for their short-lived 5th-century kingdom upon the Roman frontier, near present-day Krems an der Donau in Austria. This kingdom, like those of the neighbouring Heruli and Sciri, first appears in records after the death of Attila in 453. The Rugii, Heruli, Sciri and others are believed to have moved into this region from distant homelands, and become part of Attila's Hunnic empire which also moved and came to be based in this region. The Rugii were subsequently part of the alliance which defeated Attila's sons and the Ostrogoths at the Battle of Nedao in 454, giving their kingdom independence. In 469 they were part of a similar alliance who lost to the Ostrogoths at the Battle of Bolia, weakening their kingdom significantly.

Many Rugii, once again along with Sciri, Heruli and other Danubians, joined Odoacer in Italy and became part of his kingdom there. Fearing new plots against him, he nevertheless invaded the Rugian kingdom in 487, and the Rugian lands were then settled by the Lombards from the north. Most Rugii still in the Danubian region eventually joined the Ostrogoth Theoderic the Great who killed Odoacer and replaced him with a Gothic-led regime in Italy. The Rugii were based in Pavia and played an important role in the Italian kingdom until it was destroyed by Justinian. The third last king was the Rugian Eraric who died in 541. After him these Rugii disappear from history.

The 5th century is the time period from AD 401 (represented by the Roman numerals CDI) through AD 500 (D) in accordance with the Julian calendar. The 5th century is noted for being a period of migration and political instability throughout Eurasia.

It saw the collapse of the Western Roman Empire, which came to a formal end in 476 AD. This empire had been ruled by a succession of weak emperors, with the real political might being increasingly concentrated among military leaders. Internal instability allowed a Visigoth army to reach and ransack Rome in 410. Some recovery took place during the following decades, but the Western Empire received another serious blow when a second foreign group, the Vandals, occupied Carthage, capital of an extremely important province in Africa. Attempts to retake the province were interrupted by the invasion of the Huns under Attila. After Attila's defeat, both Eastern and Western empires joined forces for a final assault on Vandal North Africa, but this campaign was a spectacular failure.