Ordos Plateau
In Chinese accounts, the Xiongnu first appear at Ordos in the "Yizhoushu" and "Shanhaijing" during the Warring States period before it was occupied by Qin and Zhao. It is generally thought to be their homeland, however when exactly they came to occupy the region is unclear, and it might have been much earlier than traditionally thought, as suggested by archaeological finds. As the Xiongnu expanded southward into Yuezhi territory around 160 BC under their leader Modun, the Yuezhi in turn defeated the Sakas (Scythians) and pushed them away at the Issyk Kul. It is thought the Xiongnu also occupied the Ordos area during the same period, when they came in direct contact with the Chinese. From there, the Xiongnu conducted numerous devastating raids into Chinese territory (167, 158, 142, 129 BC). The Han Dynasty started to fight the Xiongnu in the 2nd century BC under emperor Han Wudi, and colonized the area of the Ordos under Shuofang commandery in 127 BC. Prior to the campaign, there were already commanderies established earlier by Qin and Zhao until they were overrun by the Xiongnu in 209 BC.
Xiongnu
In 318, after suppressing a coup by a powerful minister in the Xiongnu-Han court, in which the emperor and a large proportion of the aristocracy were massacred), the Xiongnu prince Liu Yao moved the Xiongnu-Han capital from Pingyang to Chang'an and renamed the dynasty as Zhao (Liu Yuan had declared the empire's name Han to create a linkage with Han Dynasty—to which he claimed he was a descendant, through a princess, but Liu Yao felt that it was time to end the linkage with Han and explicitly restore the linkage to the great Xiongnu chanyu Maodun, and therefore decided to change the name of the state. (However, this was not a break from Liu Yuan, as he continued to honor Liu Yuan and Liu Cong posthumously; it is hence known to historians collectively as Han Zhao).