not really fun "fact." This rumor keeps showing up whenever there's a mention of Beijing's forbidden city.

The chief architect and engineer, appointed by emperor Yongle, is Kuai Xiang, a Han Chinese dude. Among him there were several other architects, designers and engineers, and Nguyễn An was one of them. He was given order to supervise the construction of the city walls and later on, the rebuilding of the three main halls after they got burn down due to lightning.

The sources that the Vietnamese use to purport that Nguyễn An single handily designed and built the forbidden city are all Vietnamese and this one Cambridge textbook of the history of China ). And none of the Vietnamese sources are scholarly or peer reviewed sources.

As an art historian, it pains me to see rumor get perpetuated over and over