The steppe empire whose enemies nicknamed it wriggling worms
For about two centuries the Rouran ruled a domain stretching across Mongolia to Xinjiang and Kazakhstan, raiding northern China and taxing the Silk Roads. Their Tuoba rivals mocked them in writing with a pun meaning wriggling worms. They may also have given the world the title khan, and possibly the Avars of Hungary.
The confederation's founder, Yujiulu Shelun, descended from a Xianbei slave named Mugulu. The Rouran earned a warrior reputation after the Xianbei moved south into China in the late 3rd century, but stayed fragmented until 402 AD, when Shelun won over every chieftain. Conflict with the Northern Wei dynasty started at once and barely stopped. The Rouran pushed west, beat the Tiele and made the Hephthalites their vassals; those Hephthalites later adopted the Rouran ruler's title of khan.
Chinese chronicles disagree on their roots. Some link them to the older Xiongnu, while the Book of Wei traces them to the Donghu, generally considered Proto-Mongols, and genetic tests on Rouran remains point to Donghu-Xianbei ancestry on the male line. Even the name is debated: one scholar connects it with a Mongolic word for companion, meaning a warlord's sworn band, while another argues it began as a byname for the chief Cheluhui, perhaps marking him as a servant of the Wei.
Their economy relied on extracting wealth from farming neighbours at a distance, through raids, extortion and control of trade routes and oasis towns such as Gaochang. A Wei adviser urged attacking in summer, when Rouran horses were tied up with breeding and foals and the nomads could be cut off from pasture and water. The rivalry swung between wars and royal marriages; in 492 the Wei emperor sent 70 thousand horsemen north, an expedition whose outcome Chinese sources never record. Politics inside the khaganate could be brutal: when soldiers decided Heaven favoured a victorious uncle, Nagai, over the reigning khan, they killed the khan and put Nagai on the throne.
A rebellion by the Gokturks, a people the Rouran had once resettled in the Altai, brought the state down in the mid-6th century. Some survivors may have become Tatars; others possibly fled west to become the Pannonian Avars, whom the Gokturks called runaway subjects. That link remains controversial, though a recent DNA study traced the Avar elite to the Mongolian plains.
Source: Rouran Khaganate
