What is a Volkswanderung?
IIRC, Volkswanderung [German term] = [great] wandering of the peoples, supposedly started with the Huns [hsiung-nu in Chinese sources] in about early 3rd century AD, proceeded as an avalanche of displaced tribes from Eastern Central Asia westward, got to Europe in the 5th century, got deflected and dissipated, but ultimately resulted in the collapse of Western Roman empire and the establishment of a bunch of tribal kingdoms and duchies, aka Dark Ages.