Before revision: The oldest source in Bhutanese tradition is Rgyal rigs ’byung khungs gsal ba’i sgron me, written by a monk from Eastern Bhutan in 1678 C.E.
After revision: The oldest source in Bhutanese tradition is Rgyal rigs ’byung khungs gsal ba’i sgron me, written by a monk from Eastthat covers Tsangma comprehensively Bhutan in 1678 C.E.