Limbu language is one of the few Sino-Tibetan languages of the central Himalayas with their own scripts. The Limbu script or Sirijanga script was devised during the period of Buddhist expansion in Sikkim in the early 18th century when Limbuwan still constituted part of Sikkimese territory. The Limbu script was probably designed roughly at the same time as the Lepcha script (during the reign of the third King of Sikkim, Phyag-dor Nam-gyal (ca. 1700-1717)). However, it is widely believed that the Limbu script (Sirijanga) had been designed by the Limbu King Sirijanga Hang in the 9th century. The Sirijanga script was later redesigned and re-introduced by Te-ongsi Sirijunga Xin Thebe . As Te-ongsi Sirijunga Xin Thebe spent most of his time in the development of Yakthungpan, Yatkhung culture, and Limbu script; he is considered as the reincarnation of the 9th century King Sirijanga.