Chenla was recognized by a foreign power as a separate political entity at the end of the sixth century, Bhavavarman I its independent ruler. Considerable scholarly discord prevails regarding the exact geographic origin, the extent, dynamic and chronology of territorial expansion and in particular, the religious and political center of Chenla and whether or not it consisted of a unified people under a single leader. Late 20th century scholars "began cautiously to move away from the established historiographical framework" which had been laid out mainly by George Cœdès, who relies on external sources, specifically the Chinese annals, for its reconstruction. Michael Vickery suggests that ancient authors allocated the name "Chenla" to numerous small principalities and bundled them up as one singular entity in order to classify a larger number of people under the same characteristics, omitting distinctions between individual states. This approach explains why there was a noticeable increase in stone inscriptions during the seventh century. Multiple independent territories would produce their own recordings and written regulations, whereas in one polity only a tiny elite would be allowed access to such tasks. Before historians had begun to analyse and use epigraphic sources in great numbers, all available evidence supported the idea that the center of the Chenla principality must be located at Mount Phu Kao - Lingaparvata (the mountain of the linga) in Champasak Province, Laos once belonging to the Champa civilization. The local Vat Phou stele mentions the name of King Devanika (Fan Chen-ch'eng), king of kings - yet researchers do not relate the monarch to the "Dangrek Chieftains". Contrary to the academic conclusions, Cambodian legend tells that "the origin of the kings of Cambodia goes back to the union of the hermit Kambu Svayambhuva, eponymic ancestor of the Kambujas, with the celestial nymph Mera, who was given to him by Siva." The king Srutavarman was born of this couple, who was followed by his son, king Sreshthavarman. This king gave his name to Sreshthapura - believed to be Vat Phou. At the end of the sixth century, Bhavavarman and Chitrasena (royal title: Mahendravarman) attacked Funan together and subdued it around 627–649. The obvious fact that Funan and Chenla are "vague concepts" that do not apply to a tribe, a nation or a people is at odds with the Cambodian legends of origin. Folklore follows an unflinching narrative like that of a single ruler such as King Devanika -