Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million (2009). The capital of the province is Kunming. The province borders Myanmar, Laos, and Vietnam.
Yunnan is situated in a mountainous area, with high elevations in the northwest and low elevations in the southeast. Most of the population lives in the eastern part of the province. In the west, the relative height from mountain peaks to river valleys can be as much as . Yunnan is rich in natural resources and has the largest diversity of plant life in China. Of the approximately 30,000 species of higher plants in China, Yunnan has perhaps 17,000 or more. Yunnan's reserves of aluminium, lead, zinc and tin are the largest in China, and there are also major reserves of copper and nickel.
Yunnan became part of the Han Dynasty (206 BC-220 AD) during 2nd century BC. It became the seat of a Tibeto-Burman speaking kingdom known as the Kingdom of Nanzhao in the 8th century AD. Nanzhao was multi-ethnic, but the elite most likely spoke a northern dialect of Yi, which became established as the prestige dialect (see Nuosu language). The Mongols conquered the region in the 13th century, with local control exercised by warlords until the 1930s. As with other parts of China's southwest, Japanese occupation in the north during World War II forced a migration of majority Han people into the region. Ethnic minorities in Yunnan account for about 34 percent of its total population. Major ethnic groups include Yi, Bai, Hani, Zhuang, Dai and Miao.
The Yuanmou Man, a Homo erectus fossil unearthed by railway engineers in the 1960s, has been determined to be the oldest known hominid fossil in China. By the Neolithic period, there were human settlements in the area of Lake Dian. These people used stone tools and constructed simple wooden structures.
Around the 3rd century BC, the central area of Yunnan around present day Kunming was known as Dian. The Chu general Zhuang Qiao (庄跤) entered the region from the upper Yangtze River and set himself up as "King of Dian". He and his followers brought into Yunnan an influx of Chinese influence, the start of a long history of migration and cultural expansion.
In 221 BC, Qin Shi Huang unified China and extended his authority south. Commanderies and counties were established in Yunnan. An existing road in Sichuan – the "Five Foot Way" – was extended south to around present day Qujing (曲靖), in eastern Yunnan. In 109 BC, Emperor Wu sent General Guo Chang (郭昌) south to Yunnan, establishing Yizhou commandery and 24 subordinate counties. The commandery seat was at Dianchi county (present day Jinning 晋宁). Another county was called "Yunnan", probably the first use of the name. To expand the burgeoning trade with Burma and India, Emperor Wu also sent Tang Meng (唐蒙) to maintain and expand the Five Foot Way, renaming it "Southwest Barbarian Way" (西南夷道). By this time, agricultural technology in Yunnan had improved markedly. The local people used bronze tools, plows and kept a variety of livestock, including cattle, horses, sheep, goats, pigs and dogs. Anthropologists have determined that these people were related to the people now known as the Tai. They lived in tribal congregations, sometimes led by exiled Chinese.
During the Three Kingdoms, the territory of present day Yunnan, western Guizhou and southern Sichuan was collectively called Nanzhong. The dissolution of Chinese central authority led to increased autonomy for Yunnan and more power for the local tribal structures. In AD 225, the famed statesman Zhuge Liang led three columns into Yunnan to pacify the tribes. His seven captures of Meng Huo, a local magnate, is much celebrated in Chinese folklore.
In the 4th century, northern China was largely overrun by nomadic tribes from the north. In the 320s, the Cuan (爨) clan migrated into Yunnan. Cuan Chen (爨琛) named himself king and held authority from Lake Dian (then called Kunchuan [昆川]). Henceforth the Cuan clan ruled Yunnan for over four hundred years. In 738, the kingdom of Nanzhao was established in Yunnan by Piluoge (皮罗阁), who was confirmed by the imperial court of the Tang Dynasty as king of Yunnan. Ruling from Dali, the thirteen kings of Nanzhao ruled over more than two centuries and played a part in the dynamic relationship between China and Tibet. In 937, Duan Siping (段思平) overthrew the Nanzhao and established the Kingdom of Dali. The kingdom was conquered by the Mongol Empire in 1253, with its former dynasty of the Duans incorporated into the Mongol dominion as governors general of the new province. The Mongolian prince sent to administer the region with them was killed. In 1273, Kublai Khan reformed the province and appointed the Semuren Sayid Ajall as its governor. The Yunnan Province during the Yuan Dynasty also included significant portions of Upper Burma after the Burmese campaigns in the 1270s and 1280s. But with the fall of the Yuan Dynasty in 1368, the Ming Dynasty destroyed the Yuan loyalists led by Basalawarmi in the Ming conquest of Yunnan by the early 1380s.
During the Ming and Qing dynasties, large areas of Yunnan were administered under the native chieftain system. A war with Burma also occurred in the 1760s due to the attempted consolidation of borderlands under local chiefs by both China and Burma.
Yunnan was transformed enormously by the events of the war against Japan, which caused many east coast refugees and industrial establishments to relocate to the province. It assumed great strategic significance, particularly as the Burma Road was constructed from Kunming to Lashio in Burma during this time.
From 1916 to 1917, Roy Chapman Andrews and Yvette Borup Andrews led the Asiatic Zoological Expedition of the American Museum of Natural History through much of western and southern Yunnan, as well as other provinces of China. The book, Camps and Trails in China, records their experiences.
Other notable explorers include Heinrich Handel-Mazzetti; George Forrest; Joseph Francis Charles Rock, who from 1922–1949 spent most of his time studying the flora, peoples and languages of southwest China, mainly in Yunnan; and Peter Goullart, a White Russian who studied Naxi culture and lived in Lijiang from 1940 to 1949.