麦克马洪线
In 1947, the Tibetan government wrote a note presented to the Indian Ministry of External Affairs laying claim to Tibetan districts south of the McMahon Line. In Beijing, the Communist Party came to power in 1949 and declared its intention to "liberate" Tibet. India, which had become independent in 1947, responded by declaring the McMahon Line to be its boundary and by decisively asserting control of the Tawang area (1950–51).