Question: When did the region that the Yongle Emperor sent Yang Sanbao to, become part of Qing China?

full_context: Document 1: Sino-Tibetan relations during the Ming dynasty: With the example of the Ming court's relationship with the fifth Karmapa and other Tibetan leaders, Norbu states that Chinese Communist historians have failed to realize the significance of the religious aspect of the Ming-Tibetan relationship. He writes that the meetings of lamas with the Emperor of China were exchanges of tribute between "the patron and the priest" and were not merely instances of a political subordinate paying tribute to a superior. He also notes that the items of tribute were Buddhist artifacts which symbolized "the religious nature of the relationship." Josef Kolmaš writes that the Ming dynasty did not exercise any direct political control over Tibet, content with their tribute relations that were "almost entirely of a religious character." Patricia Ann Berger writes that the Yongle Emperor's courting and granting of titles to lamas was his attempt to "resurrect the relationship between China and Tibet established earlier by the Yuan dynastic founder Khubilai Khan and his guru Phagpa." She also writes that the later Qing emperors and their Mongol associates viewed the Yongle Emperor's relationship with Tibet as "part of a chain of reincarnation that saw this Han Chinese emperor as yet another emanation of Manjusri."
Document 2: Sino-Tibetan relations during the Ming dynasty: Patricia Ebrey writes that Tibet, like Joseon Korea and other neighboring states to the Ming, settled for its tributary status while there were no troops or governors of Ming China stationed in its territory. Laird writes that "after the Mongol troops left Tibet, no Ming troops replaced them." Wang and Nyima state that, despite the fact that the Ming refrained from sending troops to subdue Tibet and refrained from garrisoning Ming troops there, these measures were unnecessary so long as the Ming court upheld close ties with Tibetan vassals and their forces. However, there were instances in the 14th century when the Hongwu Emperor did use military force to quell unrest in Tibet. John D. Langlois writes that there was unrest in Tibet and western Sichuan, which the Marquis Mu Ying (沐英) was commissioned to quell in November 1378 after he established a Taozhou garrison in Gansu. Langlois notes that by October 1379, Mu Ying had allegedly captured 30,000 Tibetan prisoners and 200,000 domesticated animals. Yet invasion went both ways; the Ming general Qu Neng, under the command of Lan Yu, was ordered to repel a Tibetan assault into Sichuan in 1390.
Document 3: Qing dynasty: With respect to these outer regions, the Qing maintained imperial control, with the emperor acting as Mongol khan, patron of Tibetan Buddhism and protector of Muslims. However, Qing policy changed with the establishment of Xinjiang province in 1884. During The Great Game era, taking advantage of the Dungan revolt in northwest China, Yaqub Beg invaded Xinjiang from Central Asia with support from the British Empire, and made himself the ruler of the kingdom of Kashgaria. The Qing court sent forces to defeat Yaqub Beg and Xinjiang was reconquered, and then the political system of China proper was formally applied onto Xinjiang. The Kumul Khanate, which was incorporated into the Qing empire as a vassal after helping Qing defeat the Zunghars in 1757, maintained its status after Xinjiang turned into a province through the end of the dynasty in the Xinhai Revolution up until 1930. In early 20th century, Britain sent an expedition force to Tibet and forced Tibetans to sign a treaty. The Qing court responded by asserting Chinese sovereignty over Tibet, resulting in the 1906 Anglo-Chinese Convention signed between Britain and China. The British agreed not to annex Tibetan territory or to interfere in the administration of Tibet, while China engaged not to permit any other foreign state to interfere with the territory or internal administration of Tibet. Furthermore, similar to Xinjiang which was converted into a province earlier, the Qing government also turned Manchuria into three provinces in the early 20th century, officially known as the "Three Northeast Provinces", and established the post of Viceroy of the Three Northeast Provinces to oversee these provinces, making the total number of regional viceroys to nine.
Document 4: Qing dynasty: Han Chinese farmers were resettled from north China by the Qing to the area along the Liao River in order to restore the land to cultivation. Wasteland was reclaimed by Han Chinese squatters in addition to other Han who rented land from Manchu landlords. Despite officially prohibiting Han Chinese settlement on the Manchu and Mongol lands, by the 18th century the Qing decided to settle Han refugees from northern China who were suffering from famine, floods, and drought into Manchuria and Inner Mongolia so that Han Chinese farmed 500,000 hectares in Manchuria and tens of thousands of hectares in Inner Mongolia by the 1780s. Qianlong allowed Han Chinese peasants suffering from drought to move into Manchuria despite him issuing edicts in favor of banning them from 1740–1776. Chinese tenant farmers rented or even claimed title to land from the "imperial estates" and Manchu Bannerlands in the area. Besides moving into the Liao area in southern Manchuria, the path linking Jinzhou, Fengtian, Tieling, Changchun, Hulun, and Ningguta was settled by Han Chinese during the Qianlong Emperor's rule, and Han Chinese were the majority in urban areas of Manchuria by 1800. To increase the Imperial Treasury's revenue, the Qing sold formerly Manchu only lands along the Sungari to Han Chinese at the beginning of the Daoguang Emperor's reign, and Han Chinese filled up most of Manchuria's towns by the 1840s according to Abbe Huc.
Document 5: Qing dynasty: China also began suffering from mounting overpopulation during this period. Population growth was stagnant for the first half of the 17th century due to civil wars and epidemics, but prosperity and internal stability gradually reversed this trend. The introduction of new crops from the Americas such as the potato and peanut allowed an improved food supply as well, so that the total population of China during the 18th century ballooned from 100 million to 300 million people. Soon all available farmland was used up, forcing peasants to work ever-smaller and more intensely worked plots. The Qianlong Emperor once bemoaned the country's situation by remarking "The population continues to grow, but the land does not." The only remaining part of the empire that had arable farmland was Manchuria, where the provinces of Jilin and Heilongjiang had been walled off as a Manchu homeland. The emperor decreed for the first time that Han Chinese civilians were forbidden to settle. Mongols were forbidden by the Qing from crossing the borders of their banners, even into other Mongol Banners and from crossing into neidi (the Han Chinese 18 provinces) and were given serious punishments if they did in order to keep the Mongols divided against each other to benefit the Qing.
Document 6: Sino-Tibetan relations during the Ming dynasty: Historians Luciano Petech and Sato Hisashi argue that the Ming upheld a "divide-and-rule" policy towards a weak and politically fragmented Tibet after the Sakya regime had fallen. Chan writes that this was perhaps the calculated strategy of the Yongle Emperor, as exclusive patronage to one Tibetan sect would have given it too much regional power. Sperling finds no textual evidence in either Chinese or Tibetan sources to support this thesis of Petech and Hisashi. Norbu asserts that their thesis is largely based on the list of Ming titles conferred on Tibetan lamas rather than "comparative analysis of developments in China and Tibet." Rossabi states that this theory "attributes too much influence to the Chinese," pointing out that Tibet was already politically divided when the Ming dynasty began. Rossabi also discounts the "divide-and-rule" theory on the grounds of the Yongle Emperor's failed attempt to build a strong relationship with the fifth Karmapa—one which he hoped would parallel Kublai Khan's earlier relationship with the Sakya Phagpa lama. Instead, the Yongle Emperor followed the Karmapa's advice of giving patronage to many different Tibetan lamas.
Document 7: Sino-Tibetan relations during the Ming dynasty: Laird writes that the Ming appointed titles to eastern Tibetan princes, and that "these alliances with eastern Tibetan principalities are the evidence China now produces for its assertion that the Ming ruled Tibet," despite the fact that the Ming did not send an army to replace the Mongols after they left Tibet. Yiu Yung-chin states that the furthest western extent of the Ming dynasty's territory was Gansu, Sichuan, and Yunnan while "the Ming did not possess Tibet."
Document 8: Sino-Tibetan relations during the Ming dynasty: Tibetan sources say Deshin Shekpa also persuaded the Yongle Emperor not to impose his military might on Tibet as the Mongols had previously done. Thinley writes that before the Karmapa returned to Tibet, the Yongle Emperor began planning to send a military force into Tibet to forcibly give the Karmapa authority over all the Tibetan Buddhist schools but Deshin Shekpa dissuaded him. However, Hok-Lam Chan states that "there is little evidence that this was ever the emperor's intention" and that evidence indicates that Deshin Skekpa was invited strictly for religious purposes.
Document 9: Qing dynasty: Qing China reached its largest extent during the 18th century, when it ruled China proper (eighteen provinces) as well as the areas of present-day Northeast China, Inner Mongolia, Outer Mongolia, Xinjiang and Tibet, at approximately 13 million km2 in size. There were originally 18 provinces, all of which in China proper, but later this number was increased to 22, with Manchuria and Xinjiang being divided or turned into provinces. Taiwan, originally part of Fujian province, became a province of its own in the late 19th century, but was ceded to the Empire of Japan in 1895 following the First Sino-Japanese War. In addition, many surrounding countries, such as Korea (Joseon dynasty), Vietnam frequently paid tribute to China during much of this period. Khanate of Kokand were forced to submit as protectorate and pay tribute to the Qing dynasty in China between 1774 and 1798.
Document 10: Qing dynasty: By the mid-18th century, the Qing had successfully put outer regions such as Inner and Outer Mongolia, Tibet and Xinjiang under its control. Imperial commissioners and garrisons were sent to Mongolia and Tibet to oversee their affairs. These territories were also under supervision of a central government institution called Lifan Yuan. Qinghai was also put under direct control of the Qing court. Xinjiang, also known as Chinese Turkestan, was subdivided into the regions north and south of the Tian Shan mountains, also known today as Dzungaria and Tarim Basin respectively, but the post of Ili General was established in 1762 to exercise unified military and administrative jurisdiction over both regions. Dzungaria was fully opened to Han migration by the Qianlong Emperor from the beginning. Han migrants were at first forbidden from permanently settling in the Tarim Basin but were the ban was lifted after the invasion by Jahangir Khoja in the 1820s. Likewise, Manchuria was also governed by military generals until its division into provinces, though some areas of Xinjiang and Northeast China were lost to the Russian Empire in the mid-19th century. Manchuria was originally separated from China proper by the Inner Willow Palisade, a ditch and embankment planted with willows intended to restrict the movement of the Han Chinese, as the area was off-limits to civilian Han Chinese until the government started colonizing the area, especially since the 1860s.
Document 11: Qing dynasty: In addition to the six boards, there was a Lifan Yuan unique to the Qing government. This institution was established to supervise the administration of Tibet and the Mongol lands. As the empire expanded, it took over administrative responsibility of all minority ethnic groups living in and around the empire, including early contacts with Russia — then seen as a tribute nation. The office had the status of a full ministry and was headed by officials of equal rank. However, appointees were at first restricted only to candidates of Manchu and Mongol ethnicity, until later open to Han Chinese as well.
Document 12: Tibet: For several decades, peace reigned in Tibet, but in 1792 the Qing Qianlong Emperor sent a large Chinese army into Tibet to push the invading Nepalese out. This prompted yet another Qing reorganization of the Tibetan government, this time through a written plan called the "Twenty-Nine Regulations for Better Government in Tibet". Qing military garrisons staffed with Qing troops were now also established near the Nepalese border. Tibet was dominated by the Manchus in various stages in the 18th century, and the years immediately following the 1792 regulations were the peak of the Qing imperial commissioners' authority; but there was no attempt to make Tibet a Chinese province.
Document 13: Sino-Tibetan relations during the Ming dynasty: Shih-Shan Henry Tsai writes that the Yongle Emperor sent his eunuch Yang Sanbao into Tibet in 1413 to gain the allegiance of various Tibetan princes, while the Yongle Emperor paid a small fortune in return gifts for tributes in order to maintain the loyalty of neighboring vassal states such as Nepal and Tibet. However, Van Praag states that Tibetan rulers upheld their own separate relations with the kingdoms of Nepal and Kashmir, and at times "engaged in armed confrontation with them."
Document 14: Sino-Tibetan relations during the Ming dynasty: Wang and Nyima argue that the Ming emperor sent edicts to Tibet twice in the second year of the Ming dynasty, and demonstrated that he viewed Tibet as a significant region to pacify by urging various Tibetan tribes to submit to the authority of the Ming court. They note that at the same time, the Mongol Prince Punala, who had inherited his position as ruler of areas of Tibet, went to Nanjing in 1371 to pay tribute and show his allegiance to the Ming court, bringing with him the seal of authority issued by the Yuan court. They also state that since successors of lamas granted the title of "prince" had to travel to the Ming court to renew this title, and since lamas called themselves princes, the Ming court therefore had "full sovereignty over Tibet." They state that the Ming dynasty, by issuing imperial edicts to invite ex-Yuan officials to the court for official positions in the early years of its founding, won submission from ex-Yuan religious and administrative leaders in the Tibetan areas, and thereby incorporated Tibetan areas into the rule of the Ming court. Thus, they conclude, the Ming court won the power to rule Tibetan areas formerly under the rule of the Yuan dynasty.
Document 15: Tibet: Qing dynasty rule in Tibet began with their 1720 expedition to the country when they expelled the invading Dzungars. Amdo came under Qing control in 1724, and eastern Kham was incorporated into neighbouring Chinese provinces in 1728. Meanwhile, the Qing government sent resident commissioners called Ambans to Lhasa. In 1750 the Ambans and the majority of the Han Chinese and Manchus living in Lhasa were killed in a riot, and Qing troops arrived quickly and suppressed the rebels in the next year. Like the preceding Yuan dynasty, the Manchus of the Qing dynasty exerted military and administrative control of the region, while granting it a degree of political autonomy. The Qing commander publicly executed a number of supporters of the rebels and, as in 1723 and 1728, made changes in the political structure and drew up a formal organization plan. The Qing now restored the Dalai Lama as ruler, leading the governing council called Kashag, but elevated the role of Ambans to include more direct involvement in Tibetan internal affairs. At the same time the Qing took steps to counterbalance the power of the aristocracy by adding officials recruited from the clergy to key posts.
ground_truth: mid-18th century
sub_queries: Where did the Yongle Emperor send Yang Sanbao? Answer: Tibet
When did Tibet become part of Qing China? Answer: mid-18th century