Diễn Châu

Diễn Châu lies on the northern coast of Nghệ An, where plains meet the sea and the hills of inland Vietnam. Its name goes back to the Tang period, and under the Lý and Trần dynasties it formed a district of Đại Việt distinct from neighbouring Nghệ An. The land and sea routes passing through the region made it part of the connection between the Red River country and the south.

During the late fourteenth century the Trần court changed Diễn Châu's administrative status, and further changes followed under Hồ Quý Ly. After the Ming conquest of Đại Việt, Lê Lợi's Lam Sơn revolt spread south into Nghệ An. By 1425 the insurgents had gained control of Diễn Châu as well as Thanh Hóa and Nghệ An, giving them a base from which to continue the struggle against Ming rule.