Byzantine Empire.

 Byzantium or Eastern Roman Empire (Imperium Romanum Orientale, Romania) (Βασιλεία Ῥωμαίων, Ῥωμανία) was a province in the late antiquity and early Middle Ages. Capital of Byzantium was Constantinople. This city was large.

The Byzantine Empire left after the Roman Empire.

This country had its own culture, laws, civilization, rules, and emperors. Byzantine Empire was powerful for that time.

People in this empire talked in Greek language. But they identified themselves as Romans. Their religion was Christianity.

Byzantine Empire was a wealthy country in the early medieval period. Eastern Roman Empire had its own schools and education.

This country had many wars during its history. Rulers of other counties wanted to conquer Byzantium.

Also, Byzantine Empire had many architectural works. Different churches and other buildings had their  own style for Middle Ages.

But later this empire lost some parts. Empire which existed several centuries fell.

Byzantine Empire left legacy. Other countries studied this history. During Renaissance (XIV-XVII centuries) culture of Byzantium helped scientists.

Source of image:

https://www.shutterstock.com/ru/image-photo/ancient-golden-byzantine-coins-emperor-portraits-418296661

Source of image:

https://www.shutterstock.com/ru/image-vector/vector-map-byzantine-empire-1351244093

Source of image:

https://www.shutterstock.com/ru/image-vector/emperor-empress-byzantine-royal-family-crown-1371897008