How did Jay Chou compose "Chrysanthemum Terrace"?

After he made "A City Full of Gold Armor", he made a title song for "A City Full of Gold Armor" called "Golden Armor", which Zhang Yimou liked

Then he was asked to make a lyrical song for the end of the film, and "Chrysanthemum Terrace" came into being. Some of the sets and sequences in the music video for "Chrysanthemum Terrace" are from "A City Full of Gold Armor".

I hope this helps