c.5th century BC: The Xiongnu, a nomadic people, inhabited the region that constitutes modern-day Mongolia and established a tribal empire.
c.200 BC: The Xiongnu carried out raids on China. By the middle of the second century BC they had seized control of much of northern and western China, but were later forced back across the Great Wall by the Chinese, to the north of the Gobi (semi-desert) and into central Mongolia.
1st century AD: China’s Han dynasty (206 BC-AD 221) repelled the Xiongnu from Gansu and Xinjiang (modern-day Xinjiang Uygur), which the Xiongnu had gradually regained.
2nd century: The Xianbei, a branch of the Donghu people (who were among the first peoples conquered by the Xiongnu), made incursions into China, south of the Great Wall, and began to establish an empire.
5th century: The Ruruan, nomadic Mongols, established an empire to the north of what is now Shanxi province, China.
546-553: Turkic tribes known to the Chinese as Tujue overthrew the Ruruan.
601: The ruler of the Western Turkics, Tardu, besieged Changan (now Xian—Hsi-an or Sian), then China’s capital, but was repelled.
629-648: The Eastern Turkics were suppressed by China’s Tang dynasty (618-907), which formed an alliance with the Uygurs, inhabitants of the area between the Altai Mountains and Lake Balkhash. The Western Turkics were also conquered by the Tang, who re-established control of Xinjiang.
744: The Uygurs seized control of Mongolia.
846: Following attacks by the Kyrgyz, the Uygur Empire collapsed.
907-1125: The Liao dynasty, founded by the Kitans, a semi-nomadic people related to the eastern Mongols, ruled in northern China.
1127: The Song dynasty (960-1279—ruled only in the south after 1127) lost northern China to an invasion of the Jin Tartars, who established the Chin dynasty. The Song continued to rule their lands in southern China.
1211: Mongol forces under Temujin (Chinghiz or Genghis Khan) began their invasion of the Chin territories.