Rouran Khaganate
Rouran (Mongolian: Нирун, Nirun; Chinese: 柔然; pinyin: Róurán; literally "soft-like"; Wade-Giles: Jou-jan), Ruanruan/Ruru (Chinese: 蠕蠕/茹茹; pinyin: Ruǎnruǎn/Rúrú; literally "wriggling insects/fodder")), Tan Tan (Chinese: 檀; pinyin: Tántán), Juan-Juan or Zhu-Zhu was the name of a confederation of nomadic tribes on the northern borders of Inner China from the late 4th century until the middle 6th century. It has sometimes been hypothesized that the Rouran are identical to the Eurasian Avars who later appeared in Europe.
The term Rouran is a Mandarin Chinese transcription of the pronunciation of the name the confederacy used to refer to itself. Ruanruan and Ruru remained in modern usage despite once being derogatory. They derived from orders given by the Emperor Taiwu of Northern Wei, who waged war against the Rouran and intended to intimidate the confederacy.
The power of the Rouran was broken by an alliance of Göktürks, the Chinese Northern Qi and Northern Zhou dynasties and tribes in Central Asia in 552.
Read more about Rouran Khaganate: Origin and Expansion, Qaghans of The Rouran