Victory over Sikkim & Darjeeling

Previously Darjeeling formed a part of dominions of the Raja of Sikkim, who had been engaged in an unsuccessful warfare against the Gorkhas. From 1780 the Gorkhas constately made inroads into Sikkim. In the Sino-Nepal treaty, Sikkim lost some of its land to Nepal and by the beginning of 19th century, they had overrun Sikkim as far-eastward as the Teesta and had conquered and annexed the Terai.