Which barbarian peoples invaded both the Eastern and Western Roman empires in the 4th-7th centuries?

The Eastern and Western Roman Empire was invaded by: Ostrogoths, Alans, Slavs, Bulgarians, Huns, Avars, Arabs.

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.