The Convention of Calcutta, defining the boundary between Tibet and Sikkim, was signed on this day in the city by Britain and China. The Viceroy of India, Lord Lansdowne and the Chinese Amban in Tibet, Sheng Tai, signed the treaty. Sikkim was described as a British Protectorate.
Tibetans refused to recognise the treaty, expressing their anger at not being consulted by the Chinese. In 1893 a protocol was added to the original convention that allowed the establishment of a British trading post in Tibet.
The treaty's failure led to the British expedition to Tibet, also known as the Younghusband expedition, from 1903 to 1904. The border would later fuel disputes between China and India.