Qin's campaign against the Xiongnu in the context of "Han-Xiongnu War"

Qin Shi Huang (Chinese: 秦始皇, Qín Shǐ Huáng, pronunciation; February 259 – 12 July 210 BC) was the founder of the Qin dynasty and the first emperor of China. Rather than maintain the title of "king" (wáng 王) borne by the previous Shang and Zhou rulers, he assumed the invented title of "emperor" (huángdì 皇帝), which would see continuous use by monarchs in China for the next two millennia.

Born in Handan, the capital of Zhao, as Ying Zheng (嬴政) or Zhao Zheng (趙政), his parents were King Zhuangxiang of Qin and Lady Zhao. The wealthy merchant Lü Buwei assisted him in succeeding his father as the king of Qin, after which he became King Zheng of Qin (秦王政). By 221 BC, he had conquered all the other warring states and unified all of China, and he ascended the throne as China's first emperor. During his reign, his generals greatly expanded the size of the Chinese state: campaigns south of Chu permanently added the Yue lands of Hunan and Guangdong to the Sinosphere, and campaigns in Inner Asia conquered the Ordos Plateau from the nomadic Xiongnu, although the Xiongnu later rallied under Modu Chanyu.

The Han–Xiongnu Wars or Sino-Xiongnu Wars, were a series of military conflicts fought from 133 BC to 89 AD between the agrarian Chinese Han Empire and the nomadic Xiongnu confederacy, although extended conflicts can be traced back as early as 200 BC and as late as 188 AD.

The Chinese civilization initially clashed with Inner Asian nomadic tribes (then collectively known as Di) that would later become the Xiongnu during the Warring States period, and various northern states built elongated fortifications (which later became the Great Wall) to defend against raids down from the Mongolian Plateau. The unified Qin dynasty, who conquered all other states under Emperor Qin Shi Huang, dispatched General Meng Tian in 215 BC in a successful campaign to expel the Xiongnu from the Ordos region (which was often used as a staging area to threaten Qin's Guanzhong heartland). However, the subsequent civil wars following the Qin dynasty's collapse gave the Xiongnu tribes, who were then unified into a large confederacy under Modu Chanyu, the opportunity to reinvade the Ordos region. After the Han dynasty was established in 202 BC, Emperor Gao tried to fight off Xiongnu invasions but had himself trapped in an ambush during the Battle of Baideng, and a truce was negotiated by bribing Modu's wife, thus ending first Han–Xiongnu War. Decades of de jure peace then followed with the Chinese gifting "harmony via marriage" to appease the Xiongnu, who still routinely raided Chinese borderlands.

Meng Tian (c. 250 BC – c.August or September 210 BC) was a Chinese inventor and military general of the Qin dynasty who distinguished himself in campaigns against the Xiongnu and in the construction of the Great Wall of China. He was the elder brother of Meng Yi. He descended from a great line of military generals and architects. His grandfather, Meng Ao (zh), was a general from the era of King Zhao; and his father, Meng Wu, was also a general who served as a deputy to Wang Jian.