Genghis Khan (Temüjin) is the son of Yesugei, the leader of the Mongolian Qiyan tribe, and his mother is Hoelun. When he was nine years old, his father was poisoned by the Tatar people, and the tribe was separated. The mother and son made a difficult living by gathering, fishing and hunting on the Onan River. He was also captured by the Taichiwu tribe and narrowly escaped. When he came of age, he married Bei Ertie of the Hongji La tribe. With the help of Wang Han and Zha Muhe of the Ke Le tribe, he recaptured his captive wife from the Merle beggars, and his power gradually grew.
After that, he joined forces with Wang Han to conquer Tata'er, and successively defeated Zha Muhe, destroyed the Kelei tribe, and broke the Naiman tribe, and unified the Mongolian plateau. In 1206, a general meeting was held at the source of the Onan River, and he was elected as Cheng Jisihan and established the Great Mongolian Kingdom. He organized his tribe into thousands of households, expanded the bodyguards of Qingxue, promulgated the Zhasa decree, and ordered people to write Mongolian in Uighur letters, laying the institutional foundation of the Mongolian state.
Before and after the founding of the People's Republic of China, he attacked Western Xia many times, forcing Western Xia to accept women's petition for peace in 1209; starting from 1211, he launched a large-scale attack on gold, and conquered Zhongdu in 1215; in 1219, because the caravan was killed, he marched westward to Khwarezm, and his troops reached as far as the Indus River and the grasslands of Eastern Europe. In 1226, he conquered Western Xia again. In July of the following year, he died of illness in the army when Western Xia was destroyed. After his grandson Kublai Khan established Yuan dynasty, he was honored as Taizu.
Cheng Jisihan unified all Mongolian tribes, ended the long-term tribal wars in the grasslands, established a well-organized military state, created writing and promulgated laws, and became one of the most far-reaching conquerors in world history. His Western Expeditions opened up transportation on the Eurasian continent and objectively promoted exchanges between the East and the West. However, the large-scale massacres and plunders during the expeditions caused a sharp decline in population and economic decline in many areas of Central Asia and North China. This cost should not be ignored.