[6] Hà Tiên became the trade center in Mekong Delta; it became the best-known port in the Gulf of Siam long before the founding of Saigon and Bangkok.

In his 1742 letter to Japanese Tokugawa shogunate in Khmer, he called himself Reachea Krong Kampucea Tiptei (រាជាក្រុងកម្ពុជាធិបតី, "king of Cambodia") and later Neak Somdec Preah Sotoat (អ្នកសម្ដចព្រះសុទត្ដ).

[5] However, Siamese sources called him both Ong Chien Chun (องเชียงชุน,[7] "Chinese general") and Phraya Rachasethi (พระยาราชาเศรษฐี), thus confusing him with Oknya Reachea Sedthei (ឧកញ៉ារាជាសេដ្ឋី), the Khmer governor of Banteay Meas.

According to Vietnamese source, in 1739, a Cambodian army led by "Nặc Bồn" invaded Hà Tiên, but was utterly defeated by Tứ.

[6] Though no Cambodian chronicle recorded this affair, Tứ's victory was highly significant since it allowed Hà Tiên to enjoy full independence from Cambodia thereafter.

In return, Outey ceded Hương Úc (mordern Sihanoukville), Cần Bột (Kampot), Trực Sâm (Chhouk), Sài Mạt (Banteay Meas) and Linh Quỳnh (Kiri Vong) to Hà Tiên.

[9] After War of the second fall of Ayutthaya, Mạc Thiên Tứ hid Siamese prince Chao Chui (เจ้าจุ้ย, Chiêu Thúy).

After the defeat of Konbaung Burma, Taksin sent a tributary mission in Canton to require the royal seal, claiming that the throne of Ayutthaya Kingdom had come to an end.

In 1771, Siamese army led by Taksin and Phraya Phiphit landed at Kampong Som (present-day Sihanoukville) and Kampot, then besieged and captured Hà Tiên.

[8] Tứ had to flee to Gia Định (modern Ho Chi Minh City) and seek refuge for Nguyễn lord.

[6] However, Thai record stated that Mạc Thiên Tứ planned to flee back to Hà Tiên, but was exposed, so Taksin arrested him.

[15] Mạc Thiên Tứ had a large number of offsprings,[15] including:[2] Thonburi dynasty Kings Royalty Siamese Foreigners Key events