Question: When did the Mongol conquest reach its peak, in the region where the Sino-Nepalese War occurred?

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: Tibet: In 821/822 CE Tibet and China signed a peace treaty. A bilingual account of this treaty, including details of the borders between the two countries, is inscribed on a stone pillar which stands outside the Jokhang temple in Lhasa. Tibet continued as a Central Asian empire until the mid-9th century, when a civil war over succession led to the collapse of imperial Tibet. The period that followed is known traditionally as the Era of Fragmentation, when political control over Tibet became divided between regional warlords and tribes with no dominant centralized authority.
Document 3: 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 4: Sino-Tibetan relations during the Ming dynasty: Kolmaš writes that, as the Mongol presence in Tibet increased, culminating in the conquest of Tibet by a Mongol leader in 1642, the Ming emperors "viewed with apparent unconcern these developments in Tibet." He adds that the Ming court's lack of concern for Tibet was one of the reasons why the Mongols pounced on the chance to reclaim their old vassal of Tibet and "fill once more the political vacuum in that country." On the mass Mongol conversion to Tibetan Buddhism under Altan Khan, Laird writes that "the Chinese watched these developments with interest, though few Chinese ever became devout Tibetan Buddhists."
Document 5: Tibet: In 1904, a British expedition to Tibet, spurred in part by a fear that Russia was extending its power into Tibet as part of The Great Game, invaded the country, hoping that negotiations with the 13th Dalai Lama would be more effective than with Chinese representatives. When the British-led invasion reached Tibet on December 12, 1903, an armed confrontation with the ethnic Tibetans resulted in the Massacre of Chumik Shenko, which resulted in 600 fatalities amongst the Tibetan forces, compared to only 12 on the British side. Afterwards, in 1904 Francis Younghusband imposed a treaty known as the Treaty of Lhasa, which was subsequently repudiated and was succeeded by a 1906 treaty signed between Britain and China.
Document 6: Himachal Pradesh: The Gurkhas, a martial tribe, came to power in Nepal in the year 1768. They consolidated their military power and began to expand their territory. Gradually, the Gorkhas annexed Sirmour and Shimla. With the leadership of Amar Singh Thapa, Gorkhas laid siege to Kangra. They managed to defeat Sansar Chand Katoch, the ruler of Kangra, in 1806 with the help of many provincial chiefs. However, Gurkhas could not capture Kangra fort which came under Maharaja Ranjeet Singh in 1809. After the defeat, the Gurkhas began to expand towards the south of the state. However, Raja Ram Singh, Raja of Siba State managed to capture the fort of Siba from the remnants of Lahore Darbar in Samvat 1846, during the First Anglo-Sikh War. They came into direct conflict with the British along the tarai belt after which the British expelled them from the provinces of the Satluj. The British gradually emerged as the paramount power. In the revolt of 1857, or first Indian war of independence, arising from a number of grievances against the British, the people of the hill states were not as politically active as were those in other parts of the country. They and their rulers, with the exception of Bushahr, remained more or less inactive. Some, including the rulers of Chamba, Bilaspur, Bhagal and Dhami, rendered help to the British government during the revolt.
Document 7: Sino-Nepalese War: The Sino-Nepalese War (), also known as the Sino-Gorkha war and in Chinese the Campaign of Gorkha (), was an invasion of Tibet by Nepal from 1788-1792. The war was initially fought between Nepalese and Tibetan armies over a trade dispute related to a long-standing problem of low-quality coins manufactured by Nepal for Tibet. The Nepalese Army under Bahadur Shah plundered Tibet under Qing rule and Tibetans signed the Treaty of Kerung paying annual tribute to Nepal. However, Tibetans requested for Chinese intervention and Sino-Tibetan forces under Fuk'anggan raided Nepal up to Nuwakot only to face strong Nepalese counterattack. Thus, both countries signed the Treaty of Betrawati as a stalemate.
Document 8: Qing dynasty: Yongzheng also inherited diplomatic and strategic problems. A team made up entirely of Manchus drew up the Treaty of Kyakhta (1727) to solidify the diplomatic understanding with Russia. In exchange for territory and trading rights, the Qing would have a free hand dealing with the situation in Mongolia. Yongzheng then turned to that situation, where the Zunghars threatened to re-emerge, and to the southwest, where local Miao chieftains resisted Qing expansion. These campaigns drained the treasury but established the emperor's control of the military and military finance.
Document 9: Sikkim: Phuntsog Namgyal was succeeded in 1670 by his son, Tensung Namgyal, who moved the capital from Yuksom to Rabdentse (near modern Pelling). In 1700, Sikkim was invaded by the Bhutanese with the help of the half-sister of the Chogyal, who had been denied the throne. The Bhutanese were driven away by the Tibetans, who restored the throne to the Chogyal ten years later. Between 1717 and 1733, the kingdom faced many raids by the Nepalese in the west and Bhutanese in the east, culminating with the destruction of the capital Rabdentse by the Nepalese. In 1791, China sent troops to support Sikkim and defend Tibet against the Gorkha Kingdom. Following the subsequent defeat of Gorkha, the Chinese Qing dynasty established control over Sikkim.
Document 10: Sino-Tibetan relations during the Ming dynasty: The Ming initiated sporadic armed intervention in Tibet during the 14th century, but did not garrison permanent troops there. At times the Tibetans also used armed resistance against Ming forays. The Wanli Emperor (r. 1572–1620) made attempts to reestablish Sino-Tibetan relations after the Mongol-Tibetan alliance initiated in 1578, which affected the foreign policy of the subsequent Qing dynasty (1644–1912) of China in their support for the Dalai Lama of the Gelug school. By the late 16th century, the Mongols were successful armed protectors of the Gelug Dalai Lama, after increasing their presence in the Amdo region. This culminated in Güshi Khan's (1582–1655) conquest of Tibet from 1637–1642 and the establishment of the Ganden Phodrang regime by the 5th Dalai Lama with his help.
Document 11: Sino-Tibetan relations during the Ming dynasty: Nevertheless, the ethno-geographic caste hierarchy favoring the Mongols and other ethnicities were accorded higher status than the Han Chinese majority. Although Han Chinese who were recruited as advisers were often actually more influential than high officials, their status was not as well defined. Kublai also abolished the imperial examinations of China's civil service legacy, which was not reinstated until Ayurbarwada Buyantu Khan's reign (1311–1320). Rossabi writes that Kublai recognized that in order to rule China, "he had to employ Chinese advisors and officials, yet he could not rely totally on Chinese advisers because he had to maintain a delicate balancing act between ruling the sedentary civilization of China and preserving the cultural identity and values of the Mongols." And "in governing China, he was concerned with the interests of his Chinese subjects, but also with exploiting the resources of the empire for his own aggrandizement. His motivations and objectives alternated from one to the other throughout his reign," according to Rossabi. Van Praag writes in The Status of Tibet that the Tibetans and Mongols, on the other hand, upheld a dual system of rule and an interdependent relationship that legitimated the succession of Mongol khans as universal Buddhist rulers, or chakravartin. Van Praag writes that "Tibet remained a unique part of the Empire and was never fully integrated into it," citing examples such as a licensed border market that existed between China and Tibet during the Yuan.
Document 12: Sino-Tibetan relations during the Ming dynasty: Laird writes that Altan Khan abolished the native Mongol practices of shamanism and blood sacrifice, while the Mongol princes and subjects were coerced by Altan to convert to Gelug Buddhism—or face execution if they persisted in their shamanistic ways. Committed to their religious leader, Mongol princes began requesting the Dalai Lama to bestow titles on them, which demonstrated "the unique fusion of religious and political power" wielded by the Dalai Lama, as Laird writes. Kolmaš states that the spiritual and secular Mongol-Tibetan alliance of the 13th century was renewed by this alliance constructed by Altan Khan and Sönam Gyatso. Van Praag writes that this restored the original Mongol patronage of a Tibetan lama and "to this day, Mongolians are among the most devout followers of the Gelugpa and the Dalai Lama." Angela F. Howard writes that this unique relationship not only provided the Dalai Lama and Panchen Lama with religious and political authority in Tibet, but that Altan Khan gained "enormous power among the entire Mongol population."
Document 13: 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 14: Treaty of Sugauli: The Treaty of Sugauli (also spelled Sugowlee, Sagauli and Segqulee), the treaty that established the boundary line of Nepal, was signed on 2 December 1815 and ratified by 4 March 1816 between the East India Company and King of Nepal following the Anglo - Nepalese War of 1814 - 16. The signatory for Nepal was Raj Guru Gajraj Mishra aided by Chandra Sekher Upadhayaya, the signatory for the Company was Lieutenant Colonel Paris Bradshaw. The treaty called for territorial concessions in which some of the territories controlled by Nepal would be given to British India, the establishment of a British representative in Kathmandu, and allowed Britain to recruit Gurkhas for military service. Nepal also lost the right to deploy any American or European employee in its service (earlier several French commanders had been deployed to train the Nepali army).
Document 15: Sino-Tibetan relations during the Ming dynasty: Discussions of strategy in the mid Ming dynasty focused primarily on recovery of the Ordos region, which the Mongols used as a rallying base to stage raids into Ming China. Norbu states that the Ming dynasty, preoccupied with the Mongol threat to the north, could not spare additional armed forces to enforce or back up their claim of sovereignty over Tibet; instead, they relied on "Confucian instruments of tribute relations" of heaping unlimited number of titles and gifts on Tibetan lamas through acts of diplomacy. Sperling states that the delicate relationship between the Ming and Tibet was "the last time a united China had to deal with an independent Tibet," that there was a potential for armed conflict at their borders, and that the ultimate goal of Ming foreign policy with Tibet was not subjugation but "avoidance of any kind of Tibetan threat." P. Christiaan Klieger argues that the Ming court's patronage of high Tibetan lamas "was designed to help stabilize border regions and protect trade routes."
ground_truth: 1642
sub_queries: Sino-Nepalese War >> location Answer: Tibet
When did the conquest of Tibet reach its peak? Answer: 1642