The Trịnh Nguyễn War was a civil conflict in Vietnam that occurred from the late 16th century to the late 18th century. It was primarily fought between the Trịnh Lords, who ruled the north, and the Nguyễn Lords, who controlled the south. This war was marked by a series of battles and territorial disputes, leading to significant political and social changes in Vietnam. The conflict stemmed from power struggles following the decline of the Lê Dynasty. The Trịnh and Nguyễn factions sought to expand their influence and control over the country, resulting in prolonged warfare that devastated the region. Ultimately, the war contributed to the fragmentation of Vietnam and set the stage for future conflicts.