Answer:
The Byzantine empire began when Constantine shifted the Roman capital to Constantinople, and endured for many centuries after the Roman lands in western Europe were overrun by barbarians. It finally fell when Constantinople was taken by the Turks in 1453.
Step-by-step explanation:
The Byzantine Empire was a state formed in 395 as a result of the division of the Roman Empire into the western and eastern parts after the death of Emperor Theodosius I. A little more than 80 years after the partition, the Western Roman Empire ceased to exist, leaving Byzantium the only historical, cultural and civilizational part left from Ancient Rome.
The permanent capital and civilization center of the Byzantine Empire was Constantinople, one of the largest cities in the medieval world of the V-XII centuries. The empire controlled the largest possessions under the emperor Justinian I (527-565), having regained for several decades a significant part of the coastal territories of the former western provinces of Rome and the position of the most powerful Mediterranean power. Subsequently, under the onslaught of numerous enemies, the state gradually lost land. After the Slavic, Bulgarian, Lombard, Visigothic and Arab conquests, the empire occupied only the territory of Greece and Asia Minor. Some gain in the 9th-11th centuries gave way to serious losses at the end of the 11th century and, finally, the final death in the middle of the XV century under the pressure of the Ottomans.