Quang Trung dies in 1792, without leaving a successor strong enough to assume leadership of the country, and the usual factionalism ensues.

By this time, Nguyen Anh and his supporters have won back much of the south from Nguyen Lu, the youngest and least capable of the Tay Son brothers.

When Pigneau de Behaine returns to Vietnam in 1789, Nguyen Anh is in control of Gia Dinh.

In the succeeding years, the bishop brings Nguyen Anh a steady flow of ships, arms, and European advisers, who supervise the building of forts, shipyards, cannon foundries and bomb factories, and instruct the Vietnamese in the manufacture and use of modern armaments.

Nguyen's cause is also greatly aided by divisions within the Tay Son leadership, following the death of Quang Trung, and the inability of the new leaders to deal with the problems of famine and natural disasters that wrack the war-torn country.

After a steady assault on the north, Nguyen Anh's forces take Phu Xuan in June 1801 and Thang Long a year later.