According to Từ điển Bách khoa toàn thư Việt Nam, the date of birth of Khúc Thừa Dụ was unknown but he was from Hồng Châu, Cúc Bồ (now Ninh Giang, Hải Dương, Vietnam).
[2][3][4] Keith Weller Taylor in his The Birth of Vietnam wrote that this background information about Khúc Thừa Dụ appeared in the 18th century in an unofficial source (dã sử) therefore one cannot draw firm conclusions from it.
[5] In the early 10th century, the Tang dynasty began to fall into chaos and could not hold its authority in Tĩnh Hải quân (now northern Vietnam)[2][3] when the Chinese jiedushi Zeng Gun with his soldiers had to abandon the region in 880.
Eventually, Khúc Thừa Dụ claimed the position jiedushi of Tĩnh Hải quân which marked the beginning of the independence of Vietnam.
[8] Trần Trọng Kim in his Việt Nam sử lược believed that it was Khúc Thừa Dụ who started a revolt and claimed the title.