Mạc dynasty
In 1592, the Mạc dynasty was forced to flee to Cao Bằng and the Lê emperors were enthroned as "de jure" Vietnamese rulers under the leadership of Nguyễn Kim, the leader of Lê Dynasty loyalists. Later, Kim was poisoned by a Mạc Dynasty general which paved the way for his son-in-law, Trịnh Kiểm, to take over the leadership. Kim's eldest son, Nguyễn Uông, was also assassinated in order to secure Trịnh Kiểm's authority. Nguyễn Hoàng, another son of Nguyễn Kim, feared a fate like Nguyễn Uông's so he pretended to have mental illness. He asked his sister Ngoc Bao, who was a wife of Trịnh Kiểm, to entreat Kiểm to let Hoàng govern Thuận Hóa, the furthest south region of Vietnam at that time.