Phú Quốc. Mạc Cửu later switched allegiance to the Nguyễn lords and recognized the authority of the Vietnamese sovereign. He sent a tribute mission to the Nguyễn court in 1708, and in return received the title of Tong Binh of Hà Tiên and the noble title Marquess Cửu Ngọc () Mạc Cửu died in 1736, his son Mạc Thiên Tứ (Mo Shilin) succeeded. A Cambodian army invaded Hà Tiên in 1739 but was utterly defeated. From then on, Cambodia did not try to resume Hà Tiên, Hà Tiên enjoyed full independence from Cambodia thereafter. Mạc Thiên Tứ's reign saw the golden age of Hà Tiên. In 1758, Hà Tiên established Outey II as puppet king of Cambodia. After War of the second fall of Ayutthaya, Mạc Thiên Tứ tried to install Prince Chao Chui (, Chiêu Thúy in Vietnamese) as the new Siamese king, but was defeated by Taksin. Hà Tiên was completely devastated by Siamese troops in 1771, Mạc Thiên Tứ had flee to Trấn Giang (modern Cần Thơ). In there, he was sheltered by Nguyễn lord. Two years later, Siamese army withdrew from Hà Tiên, and Mạc Thiên Tứ retook his principality. The French missionary Pigneau de Behaine used the island as a base during the 1760s and 1780s to shelter Nguyễn Ánh, who was hunted by the Tây Sơn army. Descriptions of this mission make reference to the local Vietnamese population of the island but not the Khmer. The British envoy John Crawfurd en route to Siam from Singapore in 1822 made a stop at Phú Quốc which he transcribed as Phu-kok in March. His entry is as follows: Western records in 1856 again mentioned the island: "... King Ang Duong (of Cambodia) apprize Mr. de Montigny, French envoy in visit to Bangkok, through the intermediary of Bishop Miche, his intention to yield Phú Quốc to France." Such a proposition aimed to create a military alliance with France to avoid the threat of Vietnam on Cambodia. The proposal did not receive an answer from the French. An 1856 publication by The Nautical Magazine describes Phú Quốc to still be part of Cambodia even though it was occupied by the Cochinchinese. The quote from the publication is: While the war between Vietnam and France was about to begin, Ang Duong sent another letter, dated November 25, 1856, to Napoleon III to warn him on Cambodian claims on the