How did this solar term come about on August 15?

On August 15, the Mid-Autumn Festival began with Tang enjoying the moon. August 15th of the lunar calendar is the traditional Mid-Autumn Festival. As the season of the New Year, the Mid-Autumn Festival came into being late, but enjoying the moon has a long history. In the Eastern Jin Dynasty, playing with the moon in Niuzhu, Nanjing was the most influential story of enjoying the moon, which even evolved into the Mid-Autumn Festival enjoyed by the broad masses of people for thousands of years.