The civil war amongst the Lê-Trịnh and Mạc dynasties ended in 1592, when the army of Trịnh Tùng conquered Hanoi and executed king Mạc Mậu Hợp. Survivors of the Mạc royal spouse and children fled on the northern mountains inside the province of Cao Bằng and continued to rule there https://vf55576420.tinyblogging.com/getting-my-việt-nam-to-work-74768068