Lý Long Tường (; 1174–?) was a prince of the Lý Dynasty of Đại Việt (in modern-day Vietnam) and later became Lee Yong-sang (이용상) of Hwasan, a general of Korea. He is an ancestor of one branch of the Lee (or Rhee) family today in both South and North Korea.
Lý was born in 1174, the seventh son of Emperor Lý Anh Tông (who reigned from 1138–75) and his consort Le My Nga. He was appointed the Great National Tutor.
In 1225, Trần Thủ Độ overthrew the Lý Dynasty by introducing his nephew Trần Cảnh to the imperial court to serve the incumbent Empress Lý Chiêu Hoàng, he then orchestrated a political marriage between Trần Cảnh and Lý Chiêu Hoàng and thereafter forced Lý Chiêu Hoàng to abdicate in favour of her husband Trần Cảnh. This marked the end of the Lý Dynasty and the beginning of the Trần Dynasty. With the Trần family having just gained the throne, Trần Thủ Độ ordered the massacre of the Lý family members and forced all of its descendants to change their surname to Nguyen, and sent them to the northern mountainous areas.
In 1226, (Kien Trung's year of the Second Trần Dynasty of Thai Tong), in order to avoid further bloodshed by the Trần family, Lý Long Tường, together with 6000 mandarins and servants departed from the Than Phu (now Thanh Hóa Province) estuary and fled to the South China Sea in three large ships. They carried relics with them, including the imperial crown, imperial costumes, and the heaven imperial sword (Thượng phương bảo kiếm). After a month on the high seas, they were forced to land in Taiwan due to a typhoon. When Lý Long Tường decided to leave, his son Ly Long Hien was severely ill and had to stay in Taiwan together with 200 mandarins, followers and servants. Lý Long Tường continued northwards to Ongjin County and then on to Haeju, Hwanghae in the Yellow Sea. Legend has it that the Korean king Kojong of the Goryeo Dynasty (1192–1259) had dreamt of a grand phoenix flying from the south and landing in his nation. Therefore, he ordered the local government of Hae-ju to give the Vietnamese royal refugees a red-carpeted welcome and allow them to live in a manor in his country.