Mezue ahịrịokwu na-esonụ: Ndị agha Gorkha si Nepal wakporo Darjeeling na 1780s, wakporo isi obodo Sikkim nke Rabdentse, ma jikọta ókèala ruo Osimiri Teesta na Nepal. Ka ọ na-erule 1816, ógbè nile a maara dị ka British Sikkim ghọrọ nke Nepal. Mgbe ndị
Agha Anglo-Gorkha, Nepal nyefere otu ụzọ n'ụzọ atọ nke ókèala ya na ndị Britain n'okpuru nkwekọrịta Sugauli nke 1816, nke gụnyere mpaghara ala dị n'etiti Osimiri Mechi na Teesta. Na 10February 1817, ndị Britain weghachiri mpaghara ala dị n'etiti Mechi na Teesta na Sikkimese Chogyal n'okpuru Nkwekọrịta nke Titalia.