But this would've come as a great surprise to the millions of people

who lived in the Roman Empire up through the Middle Ages.

This medieval Roman Empire,

which we usually refer to today as the Byzantine Empire,

began in 330 CE.

That's when Constantine, the first Christian emperor,

moved the capital of the Roman Empire to a new city called Constantinople,

which he founded on the site of the ancient Greek city Byzantion.

When the Visigoths sacked Rome in 410

and the Empire's western provinces were conquered by barbarians,

Constantine's Eastern capital remained the seat of the Roman emperors.

There, generations of emperors ruled for the next 11 centuries.

Sharing continuity with the classical Roman Empire

gave the Byzantine empire a technological and artistic advantage over its neighbors,

whom Byzantines considered barbarians.

In the ninth century, visitors from beyond the frontier

were astonished at the graceful stone arches and domes

of the imperial palace in Constantinople.

A pair of golden lions flanked the imperial throne.

A hidden organ would make the lions roar as guests fell on their knees.

Golden birds sung from a nearby golden tree.

Medieval Roman engineers even used hydraulic engines

to raise the imperial throne high into the air.

Other inherited aspects of ancient Roman culture

could be seen in emperors' clothing,

from traditional military garb to togas,

and in the courts,

which continued to use Roman law.

Working-class Byzantines would've also had similar lives

to their Ancient Roman counterparts;

many farmed or plied a specific trade,

such as ceramics,

leatherworking,

fishing,

weaving,

or manufacturing silk.

But, of course, the Byzantine Empire

didn't just rest on the laurels of Ancient Rome.

Their artists innovated, creating vast mosaics and ornate marble carvings.

Their architects constructed numerous churches,

one of which, called Hagia Sophia,

had a dome so high it was said to be hanging on a chain from heaven.

The Empire was also home to great intellectuals such as Anna Komnene.

As imperial princess in the 12th century,

Anna dedicated her life to philosophy and history.

Her account of her father's reign is historians' foremost source

for Byzantine political history at the time of the first crusade.

Another scholar, Leo the Mathematician,

invented a system of beacons that ran the width of the empire—

what's now Greece and Turkey.

Stretching more than 700 kilometers,

this system allowed the edge of the Empire to warn the emperor of invading armies

within one hour of sighting them at the border.

But their advances couldn't protect the Empire forever.

In 1203, an army of French and Venetian Crusaders

made a deal with a man named Alexios Angelos.

Alexios was the son of a deposed emperor,

and promised the crusaders vast riches

and support to help him retake the throne from his uncle.

Alexios succeeded, but after a year,

the population rebelled and Alexios himself was deposed and killed.

So Alexios's unpaid army turned their aggression on Constantinople.

They lit massive fires,

which destroyed countless works of ancient and medieval art and literature,

leaving about one-third of the population homeless.

The city was reclaimed 50 years later by the Roman Emperor Michael Palaiologos,

but his restored Empire never regained all the territory

the Crusaders had conquered.

Finally, in 1453, Ottoman Emperor Mehmed the Conqueror captured Constantinople,

bringing a conclusive end to the Roman Empire.

Despite the Ottoman conquest,

many Greek-speaking inhabitants of the Eastern Mediterranean

continued to call themselves Romans until the early 21st century.

In fact, it wasn't until the Renaissance

that the term “Byzantine Empire” was first used.

For Western Europeans,

the Renaissance was about reconnecting with the wisdom of antiquity.

And since the existence of a medieval Roman Empire

suggested there were Europeans who'd never lost touch with antiquity,

Western Europeans wanted to draw clear lines between the ages.

To better distinguish the classical, Latin-speaking, pagan Roman Empire

from the medieval, Greek-speaking, Christian Roman Empire,

scholars renamed the latter group Byzantines.

And thus, 100 years after it had fallen, the Byzantine Empire was born.