The Simla Accord (Shimula tiaoyue 西姆拉條約, called so because the negotiations took place in Simla/Shima, Himachal Pradesh), negotiated during the Simla Conference between Great Britain, Tibet, and the Republic of China 中華民國 (1912-1949) on July 3, 1914, stipulated that Outer Tibet (Waizang 外藏, Amdo and Eastern Kham, also called Eastern Tibet) came under the suzerainty of China, while Inner Tibet (Neizang 內藏, Ü-Tsang and Western Kham) were independent under the government of Lhasa. It also defined the borders between the three states (Great Britain for the Crown colony of India), and in particular that between Tibet and India (the so-called McMahon Line, Makemahong xian 麥克馬洪綫), but the Chinese plenipotentiary rejected the accord because disputes over the boundary could not be solved. China did not sign the Simla Accord and thus not accept neither the Tibetan-Indian boundary as fixed by the Accord, nor the treatment of Tibet as an independent state.
According to the Accord, the territory of Tibet was understood as part of the Chinese territory (Schedule, 1), but no Tibetan representatives were sent to the Chinese parliament (Schedule, 4); the election of a Dalai Lama had to be reported to the Chinese government, and his titles to be understood as conferred by China (Schedule, 2); officials of Outer Tibet were appointed by Lhasa (Schedule, 3).
With the "liberation" of whole China, Tibet also came into the orbit of communism, who practically pursued the intention to reinstate China as it had been in 1911 (apart from Outer Mongolia, which was in the meantime transformed, with Soviet support, into the Monglian People's Republic, 1924-1992). Tibet had been part of the Qing empire 清 (1644-1911) since the late 18th century, and some Chinese historians extended territorial dependence back into the Tang period 唐 (618-907), when the king of Tibet accepted the suzerainty of the Chinese emperor.
With the death of the 13th Dalai Lama (r. 1879-1933) a power vacuum opened in Tibet, which added to the quite autarchic character of the whole country. The vacuum was for some time filled by the informal regent Künpé-la (1905-1963), who had created the first relatively modern army of Tibet, the Drongdrak Regiment, but did not make use of it to usurp power. In the end, his regiment disintegrated and he was forced into exile in 1937. In the meantime, a Prime Minister (Langdün) was selected, and a clerical regent (Reting Rinpoché) as well (both installed in 1934). Some members of the Tibetan aristocracy had studied abroad and the one or other, mainly Lungshar (d. 1938), was convinced that Tibet was ripe for a constitutional reform, mainly regarding a formally elected national assembly. Yet Lungshar was denounced being a communist and was arrested and mutilated.
The feeble political situation of Tibet encouraged the government of the Republic of China to send a legation to negotiate about the status of Tibet vis-à-vis China. The KMT planned to reintegrate Tibet into China, even if it had been practically autonomous since the downfall of the Qing. The Republican government created a Tibetan and Mongolian Affairs Commission (Meng-Zang weiyuanhui 蒙藏委員會, 1912-1928 called Meng-Zang shiwuyuan 蒙藏事務院), headed by General Huang Musong 黄慕松 which had to deal with military conflicts in the province of Xikang 西康 (Eastern Tibet) that was located between Central Tibet and Sichuan.
The Tibetans in 1934 sharply rejected Huang Musong's claim that Tibet was part of China, but allowed that a radio station was left back in Lhasa which made propaganda of the unity of Tibet with China. Yet internal problems and those with Japan distracted the attention of the Republican government from Tibet. In summer 1937 the incarnation of the Dalai Lama was found in Amdo (today in Qinghai), and could only with difficulties—and with the support of the KMT government—released from the territory of the local warlord and be brought to Lhasa. The Fourteenth (and present) Dalai Lama, called Tenzin Gyatso, was enthroned in February 1940. The Tenth Panchen Lama, Chöki Gyeltsen (1938-1989) was, had been installed somewhat earlier, but this decision was not official sanctioned by the government in Lhasa.
The reign of Reting Rinpoché was characterized by his boundless self-enrichment and neglect of the infrastructure and the army, and he did not keep celibacy, which disqualified him as a preceptor of the Dalai Lama. The ordination in 1942 was therefore carried out by an elderly monk, Takdra Rinpoché (1874-1852). Reting himself attempted a coup d'état in 1947 which failed and ended with the conspirator's death. This affair brought to light how unprepared the Tibetan government was for internal shocks, and that it could not withstand eventual external challenges. Reformers therefore won the ears of the authorities. The need for reforms had been recognized even earlier. In 1939 students had founded the Tibetan Communist Party, and some aristocrats the Tibetan Improvement Party.
The foundation of the People's Republic changed the overall situation of Tibet, and the country was confronted with a thoroughly new political order. India, a natural and historical ally, was not interested in backing Tibet at the risk of challenging other powers. The CCP announced that the PLA would liberate Tibet from feudalism and imperialism, even if the latter did not play any role at all. The Chinese embassy in Lhasa was closed, and the small army was upgraded. Outer Tibet was conquered in early 1950 and transformed into the province of Qinghai 青海, while parts of it were integrated into the provinces of Gansu and Sichuan.
On October 7, 1950, the PLA advanced in two columns, one from Shaanxi, and one from Sichuan, and soon conquered Chamdo. The local Tibet army surrendered and had thus less than 200 casualties (Kapstein 2006: 280). The high command of the invasion army under Deng Xiaoping signaled the Tibetan government, the kashak, that Tibetan traditions, above all religion, would be respected and the political and military systems not changed. Nonetheless panic befell the authorities in Lhasa, and the oracle recommended to transfer the power from the regent Takdra to the 15-year-old Dalai Lama, Tenzin Gyatso, which happened on November 17, 1950. His seat and that of the kashak were transferred to Yadong at the border to India, while Lukhang and Lozang Trashi were left in Lhasa as acting prime ministers. The government tried to bring the case before the United Nations, but the General Assembly declined, facing the much more critical crisis of the Korean War. India, for its part, was preoccupied with border quarrels over Kashmir with Pakistan.
Tibet therefore decided to enter negotiations with China, and sent representatives to Beijing in April 1951. Pressed urgently, they accepted Chinese conditions on May 23, and signed the Seventeen-Point Agreement for the Peaceful Liberation of Tibet (Guanyu heping jiefang Xizang banfa de xieyi 关于和平解放西藏办法的协议, also called Shiqi tiao xieyi 十七条协议). The people was urged to "drive out the aggressive forces of imperialism" and to return to the "big family of the Chinese motherland" (Art. 1). The local government had to support the advancement of the PLA and consolidate national defenses (Art. 2). China promised to grant local autonomy and not to alter the existing political system , including the position and powers of the Dalai Lama and the Panchen Lama (Art. 4-6), and to respect religious beliefs, customs, and habits as promised in the Common Program (Art. 7). All lamaseries were to be protected, and their income guaranteed as before (Art. 7). The Chinese insisted on a certain candidate for the position of the Panchen Lama. Even if this was not a political, but rather a religious matter, the Tibetan authorities agreed. The army was to be reorganized (Art. 8), and foreign affairs were to be taken over by Beijing (Art. 14). The central government would see to it that education and the economy would step by step develop (Art. 9-10), without any pressure (Art. 11). The traditional administration of Tibet was supplemented by creation of a military and administrative committee (junzheng weiyuanhui 军政委员会) and a military area headquarters (junqu silingbu 军区司令部) consisting of Chinese and Tibetan personnel (Art. 15).
The Dalai Lama thereupon decided to return to Lhasa, instead of seeking asylum abroad. He was accompanied from Yadong to Lhasa by General Zhang Jingwu 张经武, who immediately took over responsibility for forming a Chinese administration. The Agreement was officially accepted by the Dalai Lama on October 24, 1951.