Are the reasons for the preservation of ancient culture in Byzantium and China the same during the migration of peoples?

Are the reasons for the preservation of ancient culture in Byzantium and China the same during the migration of peoples? Which elements of culture disappeared first, and which lasted the longest?

The reasons for the stability of the culture are the same: the barbaric conquerors assimilate those elements of the culture of the conquered peoples that they do not have, but the benefits of which are obvious. In addition to administrative culture, writing and religion are adopted, which reconciled the many defeated with the winners. Intellectual achievements in the field of literature, science, philosophy, arts and crafts are often lost.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.