in 1181 with the invasion of the Cham city-state of Vijaya. In 1181 a young nobleman who was shortly to become Jayavarman VII, emerged as one of the great Khmer kings, raised an army and defeated the Chams in a naval battle. After Champa's decline began the rise of Cambodia's new enemies, the Siamese and the Vietnamese. Post-Angkor Period As some scholars assert that the decline of the Khmer Empire was, among other causes, mainly precipitated by the drain on its economy. Dynastic rivalries and slave rebellions are also considered to have affected the demise of the empire. Military setbacks Although a number of sources, such as the Cambodian Royal Chronicles and the Royal chronicles of Ayutthaya contain recordings of military expeditions and raids with associated dates and the names of sovereigns and warlords, several influential scholars, such as David Chandler and Michael Vickery doubt the accuracy and reliability of these texts. Other authors criticise this rigid "overall assessment", though. David Chandler states in A Global Encyclopedia of Historical Writing, Volume 2: "Michael Vickery has argued that Cambodian chronicles, including this one, that treat events earlier than 1550 cannot be verified, and were often copied from Thai chronicles about Thailand..." Linguist Jean-Michel Filippi concludes: "The chronology of Cambodian history itself is more a chrono-ideology with a pivotal role offered to Angkor." Similarities apply to Thai chronological records, with the notable example of the Ramkhamhaeng controversy. According to the Siamese Royal chronicles of Paramanuchitchinorot, clashes occurred in 1350, around 1380, 1418 and 1431. "In 1350/51; probably April 1350 King Ramadhipati had his son Ramesvara attack the capital of the King of the Kambujas (Angkor) and had Paramaraja (Pha-ngua) of Suphanburi advance to support him. The Kambuja capital was taken and many families were removed to the capital Ayudhya. At that time, [around 1380] the ruler of Kambuja came to attack Chonburi, to carry away families from the provinces eastwards to Chanthaburi, amounting to about six or seven thousand persons who returned [with the Cambodian armies] to Kambuja. So the King attacked Kambuja and, having captured it, returned to the capitol."[sic] Colonial Cambodia Insurrections Following negotiations by Cambodian King Ang Duong and Napoleon III for protection from Vietnam conquest and land loss by Thailand, a delegation of French naval officers concluded the French protectorate with King Norodom (1859–1904).The intervention of colonial France prevented further erosion of national and cultural integrity of Cambodia