Xiongnu
In the 1920s, Pyotr Kozlov's excavations of the royal tombs at the Noin-Ula burial site in northern Mongolia that date to around the first century CE provided a glimpse into the lost world of the Xiongnu. Other archaeological sites have been unearthed in Inner Mongolia and elsewhere; they represent the Neolithic and historical periods of the Xiongnu's history. Those included the Ordos culture, many of them had been identified as the Xiongnu cultures. The region was occupied predominantly by peoples showing Mongoloid features, known from their skeletal remains and artifacts. Portraits found in the Noin-Ula excavations demonstrate other cultural evidences and influences, showing that Chinese and Xiongnu art have influenced each other mutually. Some of these embroidered portraits in the Noin-Ula kurgans also depict the Xiongnu with long braided hair with wide ribbons, which is seen to be identical with the Ashina clan hair-style. Well-preserved bodies in Xiongnu and pre-Xiongnu tombs in the Mongolian Republic and southern Siberia show both Mongoloid and Caucasian features. Analysis of skeletal remains from sites attributed to the Xiongnu provides an identification of dolichocephalic Mongoloid, ethnically distinct from neighboring populations in present-day Mongolia. Russian and Chinese anthropological and craniofacial studies show that the Xiongnu were physically very heterogenous, with six different population clusters showing different degrees of Mongoloid and Caucasoid physical traits. These clusters point to significant cross-regional migrations (both east to west and west to east) that likely started in the Neolithic period and continued to the medieval Mongolian period.
Xiongnu
The Xiongnu-Hun hypothesis originated with the 18th-century French historian Joseph de Guignes, who noticed that ancient Chinese scholars had referred to members of tribes associated with the Xiongnu by names similar to "Hun", albeit with varying Chinese characters. Étienne de la Vaissière has shown that, in the Sogdian script used in the so-called "Sogdian Ancient Letters", both the Xiongnu and Huns were referred to as γwn ("xwn"), indicating that the two were synonymous. Although the theory that the Xiongnu were precursors of the Huns known later in Europe is now accepted by many scholars, it has yet to become a consensus view. The identification with the Huns may be either incorrect or an oversimplification (as would appear to be the case with a proto-Mongol people, the Rouran, who have sometimes been linked to the Avars of Central Europe).