On December 18, 1271, Kublai Khan of the Great Mongolia issued an edict to change the name of the country to "Dayuan" and the Yuan Dynasty was established.

Kublai Khan (Mongolian Cyrillic spelling: §å§Ò§Ú§Ý§Ñ§Û §Ó §Ñ§ß, September 23, 1215-February 18, 1294), his full name was Borzhijin Kublai Khan, Mongolian, the second son (in total) of Tuolei's wife Saolu Heteni. The founding emperor of the Yuan Dynasty in China, his temple name is Shizu, his posthumous title is Emperor Shengde Shengong Wenwu in Chinese, and his posthumous title is Emperor Xue Chan (Sečen Qa¦Ãan) in Mongolian. He also established himself as the fifth (last) Mongolian Khan, but was not universally recognized.

After his eldest brother Meng Ge ascended the throne, he ordered the attack on the Southern Song Dynasty, and Kublai Khan was in charge of the affairs of the Monan Han Dynasty. During this time, he appointed a large number of Han staff and Confucian scholars, such as Liu Bingzhong, Xu Heng, and Yao Shu, etc., and put forward the idea of "practice law". Confucian Yuan Haowen and Zhang Dehui also asked Kublai Khan to accept the title of "Confucian master", which Kublai Khan happily accepted. In 1253, Kublai Khan led an army to attack the Dali Kingdom in what is now Yunnan Province. King Duan surrendered and was appointed as the hereditary chief of Dali.

After Mengge died in 1259, the following year his brother Ali Buge was elected as the Great Khan of the Great Mongolia in Halakhun, while Kublai Khan became the Great Khan of the Central Plains under the support of elite soldiers. His younger brother Ali Buge and Kublai Khan launched a war for the throne until Ali Buge was defeated and surrendered in 1264. Kublai Khan was established as one, moved the capital to Dadu, and Shangdu became the accompanying capital, and continued to implement Han laws and appoint Han officials. However, three of the four khanates terminated their vassal relations and separated themselves from his jurisdiction because he violated the historical khanate election tradition and his proposition of "practicing Han law." Only the Ilkhanate (the first Ilkhanate, Kublai's brother Hulagu) nominally recognized Kublai's status as a great Khan, but in fact the Ilkhanate was also in a semi-independent status, and became completely independent after Kublai's death. At this point, the political territory under his actual jurisdiction only limited to the Central Plains, the eastern half of present-day Xinjiang, the entire territory of Xizang and Mongolia.

In 1271, Kublai Khan named the country Dayuan, officially ascended the throne as emperor, and began plans to attack the Southern Song Dynasty south. It took his army six years to capture the important town of Xiangyang, but progress since then was quite smooth. In 1279, during the Battle of Yashan, Lu Xiufu jumped into the sea and died on his back. The Southern Song Dynasty died, and Kublai Khan officially ruled China.

Kublai Khan later also sent troops to attack some other countries and regions. Among them, the invasion of Japan was the most famous and most tragic. In the 11th year of the Zhiyuan Dynasty (1274), the Yuan Dynasty launched the first war of aggression against Japan. Japanese history books called it the "Battle of Wenyong." With more than 32,000 people, they marched on the Eastern Expedition to Japan. In July of the 18th year of the Yuan Dynasty (1281), Kublai Khan launched the Second War of Invasion of Japan, known in history as the "Battle of Hong 'an." Fan Wenhu and Li Ting led more than 100,000 Jiangnan troops to reach the two islands of Neng and Shiga. However, they encountered a typhoon and nearly half of them drowned. Both attacks by the Yuan army ended in failure. It is generally believed that typhoons (the Japanese called these two strong winds "kamikaze") were the biggest reason for the failure. However, later generations also believed that it was caused by the incompatible marching habits of the Yuan Dynasty (the Mongolians were accustomed to fighting land, while attacking Japan was a naval battle).

Kublai Khan suffered from obesity and gout in his later years. His beloved wife Chabi and Crown Prince Jinjin passed away first, which made him deeply saddened. In order to seek psychological comfort, he enjoyed more delicious food and mellow wine. Excessive drinking put a red light on his health, and he passed away in the palace in 1294.

Comment: The period when my country's land area is the largest.