Coedès and contemporary scholars refer to the historical annals of the Sui dynasty, which mention Chenla and identify its royal residence to be near a mountain named Ling-jia-bo-po or Lingaparvata, a temple was constructed on its summit. Vat Phou is an enormously impressive Khmer Hindu temple located at the base of Mount Phu Kao in Laos, which leads theorists to speculate that Phu Kao is the mountain that is referenced in the passage and that Wat Phou could be the temple mentioned; however this view is not accepted by modern scholarship. Authors Claude Jacques and Michael Vickery question the identification of Phu Kao as Lingjiabopo/Lingaparvata because there are a number of hills in Cambodia that apply to the vague descriptions. Thus, the debate remains and the existence of Chenla as a unitary state or a capital at Vat Phou is questionable. Since there is not much evidence or writings from the time period, not much can be said about the region. The Chinese annals are one of the very few sources scholars can analyze and derive information from. Rulers Traditionally leaders were chosen based on their merit in battle and their ability to attract a large following; however, as rulers gained more power moving away from the commoners horizon, a shift from measure of capability towards patrilineal descent occurred. Adoption of the idea of the Hindu state with its consecrated military leader, the "Varman"—protector king was the ideological basis for control and supremacy. All essential elements of Bhavavarman's life and most of his descendants are known only through epigraphy. Interpreted as to be Vīravarman's successor and after gaining independence ("he has conquered his throne at the tip of his sword") ruler of the eastern portions of his father's realm, he "built a temple in 598 during his reign in [...] the center of the kingdom of Bhavapura". Mahendravarman is, according to epigraphy, also Vīravarman's son and attributed as to be the conqueror of Funan. Succession is unclear, because "this at the same time eliminates his son Bhavavarman I of the royal function" Historian Michael Vickery resolves: "Bhavavarman and...Citrasena [Mahendravarman's given name] attacked Funan" [together]. Isanavarman is the founder of a new capital - Isanapura north of the Tonlé Sap (the archaeological site of Sambor Prei Kuk). His son Bhavavarman II - is mentioned only once in an inscription in the year 644. Jayavarman I is the last ruler of a