Phú Xuân is an historic place in Huế, Vietnam. It was the capital of the Nguyễn Lords, the Tây Sơn Dynasty, and later became a part of the Nguyễn Dynasty’s capital in Huế.
In 1306, the king of Champa Chế Mân offered Vietnam two Chăm prefectures, Ô and Lý, in exchange for a marriage with Vietnamese princess Huyền Trân.[1] The Vietnamese king Trần Anh Tông accepted this offer,[1] then he took and renamed Ô and Lý prefectures to Thuận prefecture and Hóa prefecture, both of them often referred shortly as Thuận Hóa region.[1][2]
In 1592, the Mạc Dynasty was forced to flee to Cao Bằng and the Lê kings were enthroned as de jure Vietnamese rulers under the leadership of Nguyễn Kim, the leader of Lê Dynasty loyalists. Later, Kim was poisoned by a Mạc Dynasty general whick paved way to his son-in-law, Trịnh Kiểm, to take over the leadership and assassinated Kim's eldest son, Nguyễn Uông, in order to secure his authority.[3] Nguyễn Hoàng, another son of Nguyễn Kim, feared of having a fate like Nguyễn Uông so that he pretended to have mental illness and asked his sister Ngoc Bao, who was a wife of Trịnh Kiểm, to entreat Kiểm to let Hoàng govern Thuận Hóa, the furthest south region of Vietnam.[4] Because Mạc Dynasty loyalists were being revolted in Thuận Hóa and Trịnh Kiểm was busy in fighting the Mạc Dynasty forces in northern Vietnam during this time, Ngoc Bao's request was approved and Nguyễn Hoàng went south.[4] After Hoàng pacified Thuận Hóa, he and his heir Nguyễn Phúc Nguyên serectly made this region loyal to the Nguyễn family; then they rose against the Trịnh Lords.[5][6] Vietnam erupted into a new civil war between two de facto ruling families: the clan of the Nguyễn Lords and the clan of the Trịnh Lords.
The Nguyễn lords chose Thừa Thiên, a north territory of Thuận Hóa, as their family seat.[7] In 1687, in the reign of Nguyễn lord Nguyễn Phúc Trăn,[8] the construction of a citadel was started in Phú Xuân, a village of Thừa Thiên.[7][8] The citadel was a power symbol of Nguyễn family rather than a defensive building because the Trịnh lords' army could not overpass the Nguyễn lord defense in the north regions of Phú Xuân.[7] In 1744, Phú Xuân officially became capital of central and southern Vietnam after Nguyễn lord Nguyễn Phúc Khoát proclaimed himseft Võ vương (Võ King or Martial King in Vietnamese).[7] However, Tây Sơn rebellions broke out in 1771 and quickly occupied a large area of land from Quy Nhơn to Bình Thuận, thereby weakening the authority and power of the Nguyễn lords. While the war between Tây Sơn rebellion and Nguyễn lord was being occurred, the Trịnh lords sent south a massive army and easily captured Phú Xuân in 1775.[9] After the capture of Phú Xuân, the Trịnh lords general Hoàng Ngũ Phúc made a tactical alliance with Tây Sơn and withdrew almost all troops to Tonkin and left some troops in Phú Xuân.[10] In 1786, Tây Sơn rebellion defeated the Trịnh garrison and occupied Phú Xuân.[11] Under the reign of emperor Quang Trung, Phú Xuân became Tây Sơn dynasty capital.[12] In 1802, Nguyễn Ánh, a successor of the Nguyễn lords, recaptured Phú Xuân. Nguyễn Ánh rebuilt entirely the citadel and made it the center of the Nguyễn Dynasty's capital city of Huế.[7]