What are the reasons for the brilliant achievements of calligraphy and painting in Sui and Tang Dynasties?

To put it simply, it experienced the Wei, Jin, Southern and Northern Dynasties, the great ethnic integration, the economic center moving southward, the emergence and promotion of the imperial examination system, a large number of literati were enthusiastically produced, and the quality of the whole nation was improved, so that some literati had the opportunity to engage in artistic creation! Ethnic integration and ethnic exchanges have brought cultural innovation! The background of social stability also provides a good opportunity for artistic creation!