Under the Hung kings, when Văn Lang nation founded the Văn Lang tribal coalition, Quảng Bình belonged to the Việt Thường group. Under Lê Trung Hưng, this province was named Tiên Bình. The central and the south of Vietnam (from Ngang mount pass to Bình Thuận Province) was part of the Champa Kingdom. During that time, wars between Champa kingdom and Đại Việt were frequent. Majority of the wars were started by Champa Kingdom, who was then, stronger than Đại Việt. Quảng Bình became Đại Việt's territory in 1306 A.D. following the arrange marriage of the Trần Dynasty princess Huyền Trân to the Champa king, Jaya Sinhavarman III (Vietnamese: Chế Mân). Huyen Trần was King Trần Nhân Tông's daughter and King Trần Anh Tông's younger sister. Political matches made to acquire land were common traditional practices by Champa kings. Because of the marriage, Đại Việt acquired lands (as dowry) of what is now Quảng Trị Province, and Thừa Thiên-Huế Province (then known respectively as Chau O and Chau Ri or Chau Ly), the new map changed Quảng Bình from being the southernmost land and the southern border of Đại Việt. During the Trinh-Nguyễn family war in the 17th century, the Gianh River in Quảng Bình Province became the border between Dang Trong (South Vietnam) and Đàng Ngoài (North Vietnam). Đồng Hới city was built as a fortress to protect the Nguyễn family's Dang Trong from Đàng Ngoài's attacks.