The Tang Dynasty of china, the Gupta Empire of India, and the Mali Empire of Africa were similar in that each experience a period of what?

The three empires experienced a period of wealth, artistry and scientific discoveries. These time periods were considered to be the golden age of the respective empires. This was achieved through the unity of the various rulers of the opposing clans and tribes. The extensive peace and order made it possible for people to go into other pursuits than war.