Han dynasty
To the north of China proper, the nomadic Xiongnu chieftain Modu Chanyu (r. 209–174 BC) conquered various tribes inhabiting the eastern portion of the Eurasian Steppe. By the end of his reign, he controlled Manchuria, Mongolia, and the Tarim Basin, subjugating over twenty states east of Samarkand. Emperor Gaozu was troubled about the abundant Han-manufactured iron weapons traded to the Xiongnu along the northern borders, and he established a trade embargo against the group. In retaliation, the Xiongnu invaded what is now Shanxi province, where they defeated the Han forces at Baideng in 200 BC. After negotiations, the "heqin" agreement in 198 BC nominally held the leaders of the Xiongnu and the Han as equal partners in a royal marriage alliance, but the Han were forced to send large amounts of tribute items such as silk clothes, food, and wine to the Xiongnu.
Xiongnu
Attempts to identify the Xiongnu with later groups of the western Eurasian Steppe remain controversial. Scythians and Sarmatians were concurrently to the west. The identity of the ethnic core of Xiongnu has been a subject of varied hypotheses, because only a few words, mainly titles and personal names, were preserved in the Chinese sources. The name "Xiongnu" may be cognate with that of the Huns or the "Huna", although this is disputed. Other linguistic links – all of them also controversial – proposed by scholars include Iranian, Mongolic, Turkic, Uralic, Yeniseian, Tibeto-Burman or multi-ethnic.