McMahon Line
In the time that China did not exercise power in Tibet, the line had no serious challenges. In 1935, a Deputy Secretary in the Foreign Department, Olaf Caroe, "discovered" that the McMahon Line was not drawn on official maps. The Survey of India published a map showing the McMahon Line as the official boundary in 1937. In 1938, two decades after the Simla Conference, the British finally published the Simla Accord as a bilateral accord and the Survey of India published a detailed map showing the McMahon Line as a border of India. In 1944, Britain established administrations in the area, from Dirang Dzong in the west to Walong in the east.