Historically, ancient China has been one of the world's oldest empires. In ancient Chinese political theory, relations between foreign states were governed by the tributary system. Since the Emperor of China held the Mandate of Heaven, his rule was universal and extended to All under heaven. Sometimes neighboring states were actual protectorates or vassal states over which China exerted large amounts of influence, while in other cases foreign states merely acknowledged China's nominal suzerainty in order to gain access to Chinese trade, which took place through the tributary system.
Early Chinese expansions
The king of the ancient state of Qin first unified the Chinese empire in 221 BC by conquering all of the other states in what was then considered China and proclaimed himself the "First Emperor" and became known as Qin Shi Huang.
The ancient Han Dynasty (202 BC-220 AD) established control over northern Vietnam, northern Korea, and the Tarim Basin of Central Asia. The short-lived Sui Dynasty (581–618 AD) reinvaded Annam (northern Vietnam) and attacked Champa (southern Vietnam), while they also attempted to conquer Korea, which failed (see Goguryeo-Sui Wars). The later Tang Dynasty (618–907) aided the Korean Silla Kingdom in defeating their two Korean rivals, yet became shortchanged when they discovered Silla was not about to allow the Tang to claim much of Goguryeo's territory (as it had been under the Chinese Han Dynasty's control a few centuries before, the Han having wrested it from native kingdoms at that time). The Tang Dynasty established control over the Tarim Basin region as well, fighting wars with the new Tibetan Empire and stripping them of their colonies in Central Asia (which was abandoned after the An Lushan Rebellion). The Song Dynasty (960–1279), in securing maritime trade routes that ran from South East Asia into the Indian Ocean, had established fortified trade bases in the Philippines. The Mongol-lead Yuan Dynasty (1279–1368) made attempts to invade Japan after securing the Korean peninsula through the vassaldom of the Korean Goryeo dynasty, yet both of these military ventures failed (see Mongol Invasions of Japan).
Qing territorial expansion
By the late 19th century, in response to competition with other states, the Qing government of China attempted to exert direct control of its frontier areas by conquest or, if already under military control, conversion into provinces.
Ming dynasty loyalists from China invaded Taiwan and expelled Dutch colonialists from the island during the Siege of Fort Zeelandia and founded the Chinese Kingdom of Tungning. The Ming loyalists quickly moved to replace the institutions and culture of Dutch colonial rule with Han Chinese colonial rule. Language and religious institutions left by the Dutch were closed and replaced with Confucian temples and Chinese language schools for both Han Chinese and aboriginals. Officials encouraged new immigration of Han Chinese from China into territory further inland, turning aboriginal lands into new farmland.  After fighting between the Ming loyalists and the Qing during the Revolt of the Three Feudatories, the Qing attacked the Kingdom of Tungning. the Qing won the Battle of Penghu and the Ming loyalists submitted to Qing rule. Tungning was annexed as part of Fujian province. The Qing were "reluctant colonizers" but became convinced of Taiwan's value to their empire due to the threat the island posed if used as a base by rival powers, and by its abundant resources.  The Qing turned Taiwan into its own province in 1885, after Japanese interest and a defeated French invasion attempt.
After British troops invaded Tibet in the waning days of the Qing Dynasty, the Qing responded by sending Zhao Erfeng to further integrate Tibet into China. He succeeded in abolishing the powers of the Tibetan local leaders in Kham and appointing Chinese magistrates in their places by 1909–10. Qing forces were also sent to Ü-Tsang in 1910 to establish a direct control over Tibet proper, though a province was never established in this area.
Process of expansion
The ability of Qing China to project power into Central Asia came about because of two changes, one social and one technological. The social change was that under the Qing dynasty, from 1642, China came under the control of the Manchus who organised their military forces around cavalry which was more suited for power projection than traditional Chinese infantry. The technological change was advances in the cannon and artillery which negated the military advantage that the people of the Steppe had with their cavalry (although cannons and firearms were used in China centuries beforehand to combat similar threats, see Technology of Song Dynasty). Zunghar Khanate (Зүүн гарын хаант улс) was the last great independent nomadic power on the steppe in Central Asia. The Dzungars were deliberately exterminated in a brutal campaign during the Zunghar Genocide by Manchu Bannermen and Khalkha Mongols. It has been estimated that more than a million people were slaughtered, and it took generations for it to recover. The Manchu ruling family (Aisin Gioro) was a supporter of Tibetan Buddhism and so many of the ruling groups were linked by religion.
- Wills J. Jr (2006), "The Seventeenth Century Transformation", in Taiwan: A New History, Rubinstein, M. ed., M.E. Sharpe. ISBN 978-0-7656-1495-7.
- Tonio Andrade, How Taiwan Became Chinese: Dutch, Spanish, and Han Colonization in the Seventeenth Century, Columbia University Press.
- Tyler (2003), p. 55