The Imperial City of Huế is often called Đại Nội, or the Inner City, but it is only one part of a larger fortified capital. The Nguyễn emperors made Huế the capital of unified Vietnam in 1802, and it remained the political, cultural and religious center of the dynasty until 1945. Today the restored gates, walls, palace courtyards and surviving foundations sit within a living city on the banks of the Perfume River. The distinction between the wider citadel and the palace precinct helps visitors understand what they are actually entering.
UNESCO’s historical description lays out a sequence of nested spaces. Kinh Thành, the Capital City, housed administrative and military functions. Inside it, Hoàng Thành, the Imperial City, contained royal palaces and shrines. At its heart was Tử Cấm Thành, the Forbidden Purple City, reserved for the royal household. Together the two inner precincts were known as Đại Nội. Separate defensive works controlled river traffic and protected the capital from the sea. Rather than one palace, Huế was a planned urban system that combined government, ceremony, residence and defense.