the lepcha is the earliest ethnic group to have settled in sikkim. the word sikkim was derived from sukhim in limbu/subba language meaning new palace. they believe they are the autochthones while others considered that they were settled by the thirteenth century, coming from the hills before the arrival of the tibetan bhutias. the bhutia who immigrated to sikkim claimed descent from a common ancestor, a khampa prince or chief named khye-bum-sar, and were divided into fourteen main families. the limbus or the tsongs are a ethnic nepali kirati tribe indigenous to the tract west of teesta who believe they are the original inhabitants of limbuwan, a part of which is still retained in west sikkim. relations between the lepcha and tibetan peoples began in the thirteenth century with the signing of a blood brotherhood by the lepcha chief thekong tek and the tibetan prince khye bumsa at kabi lungchok in north sikkim. the bhutias introduced buddhism to the region.