For Rome, which was the most serious consequence of the invasion of the Huns?

The Huns were a nomadic people who lived in Central Asia, the Caucasus, and Eastern Europe, between the 4th and 6th century 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; the Huns' arrival is associated with the migration westward of a Scythian people, the Alans.[1] By 370 AD, the Huns had arrived on the Volga, and by 430 the Huns had established a vast, if short-lived, dominion in Europe.

In the 18th century, the French scholar Joseph de Guignes became the first to propose a link between the Huns and the Xiongnu people, who were northern neighbours of China in the 3rd century BC.[2] Since Guignes' time, considerable scholarly effort has been devoted to investigating such a connection. However, there is no scholarly consensus on a direct connection between the dominant element of the Xiongnu and that of the Huns.[3] Priscus, a 5th-century Romandiplomat and historian, mentions that the Huns had a language of their own; little of it has survived and scholars have considered whether it was related to Turkic, Mongolic, or even Tungusic language families, although the almost complete lack of a text corpus renders the language unclassifiable at present. Some researchers indeed argue, the original Huns may have had a Yeniseiantribal elite, which ruled initially over various Turkic, Mongolic, and Iranian-speaking tribes.[4] Numerous other ethnic groups were included under Attila the Hun's rule, including very many speakers of Gothic, which some modern scholars describe as a lingua franca of the Empire.[5] Their main military technique was mounted archery.

The Huns may have stimulated the Great Migration, a contributing factor in the collapse of the Western Roman Empire.[6][7] They formed a unified empire under Attila the Hun, who died in 453; after a defeat at the Battle of Nedao their empire disintegrated over the next 15 years. Their descendants, or successors with similar names, are recorded by neighbouring 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 memory of the Huns also lived on in various Christian saints' lives, where the Huns play the roles of antagonists, as well as in Germanic heroic legend, where the Huns are variously antagonists or allies to the Germanic main figures. In Hungary, a legend developed based on medieval chronicles that the Hungarians, and the Székely ethnic group in particular, are descended from the Huns. However, mainstream scholarship dismisses a close connection between the Hungarians and Huns

The Huns invasion happened in Central Asia, it is considered one of the Mongol tribes who, by moving westward towards Europe, absorbed the other nomadic tribes with them. By attacking already existing tribes like Visigoths, on the territory of Gaul, which in time caused a domino effect. Movements caused by the invasion of the Hun, have led many tribes to attack the Roman Empire, and confront the Empire with other "barbaric" tribes, leading to the collapse of the Roman Empire.