鄭梉
The Nguyễn launched their own invasion of northern Vietnam in 1653. The Nguyễn army attacked north and defeated the weakened Royal army. [[Quảng Bình Province]] was captured. Then [[Hà Tĩnh Province]] fell to the Nguyễn army. In the following year, Trịnh Tráng died as Nguyễn forces made attacks into [[Nghệ An Province]]. Under a new Trịnh Lord, the capable [[Trịnh Tạc]], the Royal army attacked the Nguyễn army and defeated it. The Nguyễn were fatally weakened by a division between their two top generals who refused to cooperate with each other. In 1656 the Nguyễn army was driven back all the way to their original walls. Trịnh Tạc tried to break the walls of the Nguyễn in 1661 but this attack, like so many before it, failed to break through the walls.