Yunnan has an area of ​​more than 390,000 square kilometers, ranking eighth in the country, about the same size as Japan, but compared with ancient times, it has indeed shrunk. In ancient times, Yunnan not only included the current province, but also included northern Myanmar, part of Laos, and even some places on Vietnam.

The name Yunnan was actually only found during the Yuan Dynasty. It was previously called Dian, or Yunzhong or something. As early as the pre-Qin period, this was an area with many ethnic minority tribes, such as the ancient Dian Kingdom, but the real formation of a unified pattern had to start with the Nanzhao Kingdom of the Tang Dynasty. Nanzhao Kingdom was established in 738. At that time, there were six large tribes around Erhai Lake, called Liuzhao, and each of them looked like a small kingdom.

Mengshezhao was in the southernmost part, and the leader Piluoge, with the support of the Tang Dynasty, annexed the other five and unified the Erhai River Basin. Emperor Xuanzong of Tang appointed him as the King of Yunnan, and the capital was first in Mengshe, which is now Weishan. Later, in 779, he moved to Yangzhumei City, which is now the old city of Dali. Nanzhao's territory is quite large. In addition to the entire Yunnan area, it also crosses the Hengduan Mountains to the west, affecting the plains of northern Myanmar, east to western Guizhou, south to northern Laos, and even the Li Dynasty in Vietnam.

Why so big? Because the Central Plains dynasty was busy with civil strife at that time, Nanzhao took the opportunity to expand, but his control was not strong, and many peripheral areas only surrendered in name only, but in fact they were in a loose state of restraint. The Nanzhao Kingdom existed for more than 160 years. In 902, the powerful minister Zheng Maisi usurped the throne and changed the name of the country to Dachanghe, and Nanzhao disappeared.

Next is Dali Kingdom, founded in 937. Duan Siping, a Bai nobleman, overthrew the Dayi Ning Kingdom and established Dali, and the capital was still Yangzhumei City. The territory is similar to that of Nanzhao, including Yunnan, southern Sichuan, western Guizhou, northern Myanmar, Laos and a few areas in Vietnam. The Dali Kingdom had a good relationship with the Song Dynasty. The Song Dynasty was busy defending the Liao and Jin Dynasties and had no time to manage the southwest, so they agreed to Dali Autonomy. Dali existed for more than 300 years and was destroyed by Mongolia in 1253.

Kublai Khan from Mongolia led his army south, attacked in three ways, and entered Yunnan from Sichuan, destroying Dali King Duan Xingzhi. After the Mongols conquered, they did not completely destroy the local forces, but instead asked the Duan family to continue to be in charge of affairs and become the chief executive of Dali, and to govern with the Mongolian King of Yunnan and Liang Kings. In 1274, the Yuan Dynasty established the Yunnan Xingzhongshu Province, with the capital on Zhongqing Road, now Kunming.

At this time, Yunnan's territory was quite wide, but the governance method was still restricted and maintained by the chieftains and Xuanwei Department. The toast is the local leader and enjoys a high degree of autonomy. For example, the Eight Hundred Wife Xuanweishu is actually the Lanna Kingdom in northern Thailand. It is nominally belonging to Yuan Dynasty, but it is actually independent. In 1290, Kublai Khan appointed his grandson Ganmala as King of Liang and guarded Yunnan. The Yuan Dynasty had weak control over the periphery, and northern Myanmar and Laos were beyond the reach. Many tribes were in independence from time to time.

In the Ming Dynasty, this matter changed. In 1382, the Ming army Lan Yu and Mu Ying led their troops to capture Dali, destroyed the Liang King of the Yuan Dynasty, changed Dali Road into Dali Prefecture, and built a new city, the current Dali Ancient City. The Ming Dynasty did not engage in the loose management of the Yuan Dynasty, but instead promoted the transformation of land and return to the current, which was to abolish the privileges of chieftains and replace them with officials sent by the central government to directly manage them.

A large number of Han people immigrated from Shandong, Jiangxi and other places to Yunnan, and the population structure changed drastically. At the end of the Ming Dynasty, Yunnan and Central Plains culture were almost integrated, and the central government had much stronger control. But in this process, the frontier became fragmented. The original Sanxuan and Liuwei Department in the Ming Dynasty. Except for the Cheli Xuanwei Department in Xishuangbanna, it was also China, and everything else was lost.

For example, Mengyang and Mengmao in Myanmar, the scenic spots of Laos, Mengla and others have successively become kingdoms. Why lose it? Because the transformation of the land and return to the flow angered the local chieftains, they resisted. Although the Ming army suppressed it, the terrain was complex and the supply was difficult, so the periphery could not be defended. In addition, neighboring countries such as Myanmar and Vietnam have risen and eroded the border. The Ming Dynasty strengthened control of the mainland and the periphery slipped away.

The Qing Dynasty inherited the path of the Ming Dynasty and continued to change its territory, but it was more thorough. During the reign of Emperor Kangxi and Yongzheng, the waste captains were established in remote areas of Yunnan, and prefectures and counties were assigned to manage the government. Immigration continues, the Han population increases, and cultural integration is deep. But the Qing Dynasty did not take back the lost territory. For example, northern Myanmar was unified by the Burmese dynasty in the mid-18th century, and the later Nguyen dynasty of Vietnam, later the Nguyen dynasty, also stabilized the southeast.

In the 19th century, Britain conquered Myanmar, France took Vietnam, the great powers squeezed from the south, and some small pieces of land were lost on the Qing Dynasty's border. During the Republic of China period, warlords fought in a melee, and Yunnan was strong in autonomy, but its territory did not grow larger. After 1949, the founding of New China and Yunnan were established, and the administrative divisions were stable, but the reduction of historical territory was a foregone conclusion. The current boundary of Yunnan Province was determined in the 1950s, including 8 cities and 8 autonomous prefectures, neighboring Tibet, Sichuan, Guizhou, Guangxi, and Vietnam, Laos, and Myanmar in the south.

Why is Yunnan getting smaller and smaller? First of all, it is geopolitical factors. Yunnan is high in northwest and low in southeast and has an altitude ranging from the Meili Snow Mountain at 6,740 meters to the Honghe Valley at 76 meters. The Hengduan Mountains are like barriers, with difficult traffic. The ancient army's supply lines are long and the cost of controlling the periphery is high. During the Dali period of Nanzhao, the mountains were naturally dangerous to expand, but they could not actually control the northern Myanmar Plain.

After the Mongolian conquest, there were many mountain tribes autonomous regions, and it was difficult for the central government to penetrate. The second is the change in governance model. The Tang, Song and Yuan dynasties were banned, and the chieftains had privileges and had great names in their territory, but they were loose. The Ming and Qing Dynasties changed their territory back to the current, with strong centralization and stable power, but the outer chieftains rebelled and went out independently. Like the Shan State in Myanmar, it was originally the Xuanwei Department of the Yuan and Ming dynasties, but later became an independent kingdom.

The third is external pressure. The Lee Dynasty and Nguyen Dynasty in Vietnam eroded the southeast, the Burmese dynasty unified the north, the rise of the kingdoms of Laos, and the British and French colonization in the 19th century, the southern part of Yunnan was squeezed. The fourth is the integration of population and culture. The Han people immigrated to the Ming and Qing Dynasties, and Yunnan was core to the Chinese, but the peripheral ethnic minorities were unwilling to integrate and had a strong tendency to separate.

From another perspective, this reduction is a process of increasing central influence. In ancient times, Yunnan was like a semi-independent kingdom, and now it is an inseparable part of the country. Economically, in the past, it relied on tribute to chieftains, but now industry, agricultural and tourism are moving forward together. Although per capita GDP is not high, it has a fast growth.

Culturally, multi-ethnic integration, coexistence between white mar and white dynasties and Yi and Dai. But the lesson of history lies in the fact that border governance must be balanced, centralized and autonomous, otherwise it will be easily fragmented. Modern China's investment in Yunnan, such as high-speed rail and highway, shortens distances and enhances cohesion.

The reduction in Yunnan actually reflects the general laws of China's border history: when the Central Plains dynasty expanded, the territory was large but empty; when internalized, the actual control was strong but small. Like Tibet, Xinjiang, has also gone through a similar process. This matter is down-to-earth, just like the company managing a branch, it was delegated to power in the early years, but it was easy to lose control; later, the power was settled, and the core might be stable, and the outside world might be single.

The case in Yunnan reminds us that history is not a straight line, and changes in territory are affected by many factors. Having said that, although Yunnan is a little small now, it has a diverse ecology and rich biological resources. It is the gateway to the southwest of China and is important to the Belt and Road Initiative. For future development, we must learn from historical experience, focus on sustainability, balanced development and protection.