Nguyễn Phúc Khoát in the context of Trà Vinh Province

The Nguyễn lords (Vietnamese: Chúa Nguyễn, 主阮; 1558–1777, 1780–1802), also known as the Nguyễn clan (Vietnamese: Nguyễn thị; chữ Hán: 阮氏), were Nguyễn dynasty's forerunner and a feudal noble clan ruling southern Đại Việt in the Revival Lê dynasty. The Nguyễn lords were members of the House of Nguyễn Phúc. The territory they ruled was known contemporarily as Đàng Trong (Inner Realm) and known by Europeans as the Kingdom of Cochinchina and as Kingdom of Quảng Nam (Vietnamese: Quảng Nam Quốc; chữ Hán: 廣南國) by Imperial China, in opposition to the Trịnh lords ruling northern Đại Việt as Đàng Ngoài (Outer Realm), known as the "Kingdom of Tonkin" by Europeans and "Kingdom of Annam" (Vietnamese: An Nam Quốc; chữ Hán: 安南國) by Imperial China in bilateral diplomacy. They were officially entitled, in Sino-Vietnamese, the Nguyễn Vương (chữ Hán: 阮王) in 1744 when lord Nguyễn Phúc Khoát self-proclaimed himself to elevate his status equally to Trịnh lords's title known as the Trịnh Vương (Vietnamese: Trịnh Vương; chữ Hán: 鄭王). Both Nguyễn and Trịnh clans were de jure subordinates and fief of the Lê dynasty. However, the de jure submission of the Nguyễn lords to the Trịnh lords ended in 1627 sparked the war between them.

While they recognized the authority of and claimed to be loyal subjects of the revival Lê dynasty, they were de facto rulers of southern Đại Việt. Meanwhile, the Trịnh lords ruled northern Đại Việt in the name of the Lê emperor, who was in reality a puppet ruler. They fought a series of long and bitter wars that pitted the two halves of Vietnam against each other. The Nguyễn were finally overthrown in the Tây Sơn wars, but one of their descendants would eventually come to unite all of Vietnam. Their rule consolidated earlier southward expansion into Champa and pushed southwest into Cambodia.

Đàng Trong (chữ Nôm: 唐冲, lit. "Inner Circuit"), also known as Nam Hà (chữ Hán: 南河, "South of the River"), was the region of Vietnam south of the Gianh River, under the lordship of the Nguyễn clan, and later expanded through Vietnamese southward expansion. It was bordered to the north by Đàng Ngoài, ruled by the Lê–Trịnh.

Throughout the 17th century and most of the 18th century, the Nguyễn lords, though claiming loyalty to the Lê emperors in Thăng Long (Hanoi), ruled Đàng Trong as a de facto independent kingdom. Nguyễn rulers titled themselves as Chúa (chữ Nôm: 主, lit. "Lord") instead of Vua (chữ Nôm: 𤤰, lit. "King") until Lord Nguyễn Phúc Khoát officially claimed the title Vũ Vương (chữ Nôm: 武王, lit. "Martial King") in 1744.