Gia Long
As Nguyễn Phúc Cảnh was the presumptive heir to Gia Long, Canh's eldest son Mỹ Đường was next in line for the succession. Gia Long however changed the primogeniture rule of succession to include "testamental measures" ("gia thien ha"), and ultimately changed his successor to his fourth son, who became emperor Minh Mạng.