Why is the Sui and Tang Dynasties the heyday of China traditional culture?

The Sui, Tang, Song and Yuan Dynasties is an important stage for the continued development of China feudal society, and it is also the heyday of China feudal society. Although there was a period of division in the middle, unity, development, prosperity and openness have always been the mainstream of this period.

So it is the heyday of China's traditional culture.