Answer
The Trịnh lords ruled the north of Vietnam from 1545 to 1788. Their territory was called the Trịnh lordship and it included the provinces of Thanh Hóa, Nghệ An, Hà Tĩnh, Quảng Bình, Quảng Trị, Thừa Thiên-Huế, and Đà Nẵng. The Trịnh lords were a powerful family who controlled the Vietnamese government for over two centuries.