The Huns, or Mongols, were a Turkish-speaking nomadic people who lived in the steppes to the north of China. The first great ruler of the Huns was Mao-tun (234 - 174 B.C.) who united the Huns in central Asia in a large military confederation that stretched as far as Turkestan.
Five hundred years later, around A.D. 350, a similar confederation formed in Mongolia, which the Chinese called Juan-juan. At its height this war confederation exerted authority from Manchuria to Lake Balkash. Whole tribes fled before their assault, among them a group which became known in European history as the Huns. The Huns moved across the sparse steppe lands of Russia and then attacked the Gothic Black Sea empire. Terrified, the Gothic peoples fled westwards into Roman territory.
Towards the end of the fifth century, another group of Huns, called the 'White Huns' stormed into India, where they destroyed the Gupta empire which brought the golden Age of Hindu civilization to an end.
The Juan-juan empire, in turn, was destroyed by Chinese armies cooperating with Turks (552) who promptly set up their own steppe empire. The Juan-juan fled westwards across the Russian steppes to the west of the Turkish Khazars, where they became known as the Avars.