Han–Xiongnu Wars in the context of "Ancient Chinese states"

The Xiongnu (Chinese: 匈奴, [ɕjʊ́ŋ.nǔ]) were a tribal confederation of nomadic peoples who, according to ancient Chinese sources, inhabited the eastern Eurasian Steppe from the 3rd century BC to the late 1st century AD. Modu Chanyu, the supreme leader after 209 BC, founded the Xiongnu Empire.

After overthrowing their previous overlords, the Yuezhi, the Xiongnu became the dominant power on the steppes of East Asia, centred on the Mongolian Plateau. The Xiongnu were also active in areas now part of Siberia, Inner Mongolia, Gansu and Xinjiang. Their relations with the Chinese dynasties to the south-east were complex—alternating between various periods of peace, war, and subjugation. Ultimately, the Xiongnu were defeated by the Han dynasty in a centuries-long conflict, which led to the confederation splitting in two, and forcible resettlement of large numbers of Xiongnu within Han borders. During the Sixteen Kingdoms era, listed as one of the "Five Barbarians", their descendants founded the dynastic states of Han-Zhao, Northern Liang and Helian Xia and during the Northern and Southern dynasties founded Northern Zhou (founded by members of the Yuwen tribe of Xiongnu origin) in northern China.

Between the Roman Empire and the Han dynasty, as well as between the later Eastern Roman Empire and various successive Chinese dynasties, there were (primarily indirect) contacts and flows of trade goods, information, and occasional travelers. These empires inched progressively closer to each other in the course of the Roman expansion into ancient Western Asia and of the simultaneous Han military incursions into Central Asia. Mutual awareness remained low, and firm knowledge about each other was limited. Surviving records document only a few attempts at direct contact. Intermediate empires such as the Parthians and Kushans, seeking to maintain control over the lucrative silk trade, inhibited direct contact between the two ancient Eurasian powers. In 97 AD, the Chinese general Ban Chao tried to send his envoy Gan Ying to Rome, but Parthians dissuaded Gan from venturing beyond the Persian Gulf. Ancient Chinese historians recorded several alleged Roman emissaries to China. The first one on record, supposedly either from the Roman emperor Antoninus Pius or from his adopted son Marcus Aurelius, arrived in 166 AD. Others are recorded as arriving in 226 and 284 AD, followed by a long hiatus until the first recorded Byzantine embassy in 643 AD.

The indirect exchange of goods on land along the Silk Road and sea routes involved (for example) Chinese silk, Roman glassware and high-quality cloth. Roman coins minted from the 1st century AD onwards have been found in China, as well as a coin of Maximian (Roman emperor from 286 to 305 AD) and medallions from the reigns of Antoninus Pius (r. 138–161 AD) and Marcus Aurelius (r. 161–180 AD) in Jiaozhi (in present-day Vietnam), the same region at which Chinese sources claim the Romans first landed. Roman glassware and silverware have been discovered at Chinese archaeological sites dated to the Han period (202 BC to 220 AD). Roman coins and glass beads have also been found in the Japanese archipelago.