In 938, after defeating the Southern Han army on the Bach Dang River, Ngo Quyen chose Co Loa as the capital, ending 1000 years of Northern domination. Ngo Quyen has 4 sons: Ngô Xương Ngập (Thiên Sách Vương), Ngô Xương Văn (Nam Tấn Vương), Ngô Nam Hưng, Ngô Càn Hưng (no information).

Ngô Xương Ngập is the eldest son of Ngô Quyền. After Ngô Quyền died, Dương Tam Kha usurped the throne, Xương Ngập was so scared that he fled to Nam Sách Giang, staying at Phạm Lệnh Công’s house in Trà Hương. When he escaped to Nam Sách, Xương Ngập got married and had a child, Ngô Xương Xí, who later became an ambassador to occupy Binh Kieu (now in Vinh Phuc province).

In 951, Xương Văn restored power to the Ngo court and welcomed his brother back to the capital. Ngô Xương Ngập claimed to be Thiên Sách Vương.

After returning to Cổ Loa, Xương Ngập became increasingly autocratic. Historian Ngo Sy Lien wrote: "Nam Tan welcomed Xương Ngập to take care of the government together, who respected his brother and wanted to share wealth. Xương Ngập should take the fact that he has no merit to give the throne to his younger brother, how much merit? Xương Ngập thought he was the eldest son, claimed to be the same king, took care of the government, and was so autocratic that Nam Tan Vuong could no longer participate in politics, it was a loss of brotherhood, very mean." A few years later, in 954, Ngo Xương Ngập died, ending the situation of one country, two kings. The power of the Ngo government was concentrated again.