Also known with the title of Lord, they had the right to choose the crown prince and had power over political and military matters.

[1] He proved to be a very capable leader and in 1571, the Lê Loyalist Army captured the Eastern capital Thăng Long from emperor Mạc Mậu Hợp.

Trịnh Tùng appointed a new emperor (Lê Thế Tông), and had the previous king assassinated.

The war against the Mạc continued for the next twenty years until 1592, when the Eastern Capital (Dong kinh) was reconquered.

In formal recognition for his defeat of the Mạc, Trịnh Tùng was given the title Pacifying Prince (Bình An Vương) in 1599.