 In 1782 , the Tây Sơn attacked Gia Định ( later known as Saigon and now Ho Chi Minh City ) again and forced Nguyễn Ánh to flee to the island of Phú Quốc under Duyệt 's escort . It was one of many times when Gia Định changed hands . In 1787 , Duyệt began organizing and commanding his own unit , and individually recruited his own enlisted men . In 1788 , the tide began to turn in favour of the Nguyễn , after Pigneau de <unk> , a French Catholic priest who befriended Nguyễn Ánh in the hope that the young prince would gain power and give special privileges to his religion , recruited French military officers to fight for the Nguyễn . In 1788 , the Nguyễn recaptured Gia Định and never relinquished it again . From then on , Nguyễn Ánh transformed the city into a fortress and his powerbase and began consolidating his hold on the surrounding area , before attacking the Tây Sơn with a view to eliminating them . 
