The Sikkim expedition, a British military expedition…

The Sikkim expedition, a British military expedition to expel Tibetan forces from Sikkim in present-day north east India, begins on March 15, 1888.

The roots of the conflict lie in British-Tibetan competition for sovereignty over Sikkim.

After the advance on Chumbi and Gangtok, military operations stall.

On December 21, the Chinese resident in Lhasa arrives at Gnathong and negotiations begin, but no agreement is reached so the Amban returns to Rinchingong, where he receives orders to wait for Mr. T. H. Hart, of the Chinese Imperial Customs Service, who finally arrives to Gnathong on March 22, 1889.

Eventually the Anglo-Chinese Convention of Calcutta is signed on March 17, 1890 at Kolkata, which establishes the Tibetan renunciation of suzerainty over Sikkim, and delimits the border between Tibet and Sikkim.