In traditional Tibetan historiography, "btsan po'i rgyal rabs" would appear to be the most common label given to this period, though "btsan po'i gdung rabs" appears as well. Strictly, speaking though, both are not really appropriate names for a polity since they literally mean "the (royal) genealogy of emperors." Likewise, "btsan po'i skabs" means "the period of the emperors," also problematic as an overall term for the polity. Tupten Püntsok, a major Tibetan historian in the late twentieth and early twenty first century, has suggested considering "chos ldan rgyal rabs", literally "the royal genealogy of the religious" as a way to signify the imperial period involving Buddhist emperors, in contrast to the earlier period of supposed emperors who were not Buddhist.