What museum is now housed in the palace built by Nguyễn An and others in the 15th century?
Nguyễn An:  He, along with numerous architects, such as master designers and planners Cai Xin (蔡信), Chen Gui (陳珪), and Wu Zhong (吳中), master carpenter Kuai Xiang (蒯祥), and master mason Lu Xiang (陸祥), was an important builder of the Forbidden City in Beijing. Forbidden City: The Forbidden City was the Chinese imperial palace from the Ming dynasty to the end of the Qing dynasty—the years 1420 to 1912. Forbidden City:  It is in the center of Beijing, China, and now houses the Palace Museum.
i don't know