The European Huns seem to have been a western extension of the Xiongnu., a group of proto-Mongol nomad tribes from north-eastern China and Central Asia.

These people achieved military superiority over their rivals (most of them highly cultured and civilized) by their splendid state of readiness for combat, amazing mobility, and weapons like the Hun bow. Attila was born around 406.
Nothing certain is known about his childhood; the supposition that at a young age he was already a capable leader and a capable warrior is reasonable but unknowable. Following negotiation of peace terms in 418, the young Atilla, at the age of 12, was sent as a child hostage to the Roman court of Emperor Honorius.
In return, the Huns received Flavius Aetius, in a child hostage exchange arranged by the Romans.