Emperor Minh Mang composed a poem, which by Imperial Decree became a code for his direct descendants:

At each generation, the princes would have for a last name, a word from the poem, in a chronological order instead of the name “Nguyen”. The princesses would have a title instead of a last name. Such title indicates their rank and generation viv-a-vis Emperor Minh Mang.

To this day, only members of the Imperial Family are allowed to bear such names and titles.

Civilians are encouraged to embrace the last name “Nguyen” as a homage and pledge of allegiance to the Nguyen Dynasty.