Trịnh Tráng was the eldest son of Trịnh Tùng. He took power after a brief succession struggle at the time of Trịnh Tùng's death. The main problem he faced during his rule was the power and independence of the Nguyễn lords who ruled the southern-most provinces of Vietnam. In modern terms the Nguyễn ruled over Thừa Thiên–Huế Province, Da Nang, Quảng Nam Province, and Quảng Ngãi Province. This was the frontier of Vietnam and, as these provinces were newly conquered from the Champa, there was new land to farm and plenty of work for ambitious men. Main article: Trịnh–Nguyễn War