The civil war involving the Lê-Trịnh and Mạc dynasties resulted in 1592, when the army of Trịnh Tùng conquered Hanoi and executed king Mạc Mậu Hợp. Survivors from the Mạc royal family members fled into the northern mountains while in the province of Cao Bằng and continued to rule there until eventually 1677 when Trịnh Tạc conq