Chapter 1: What Even Is the Byzantine Empire?

If you’ve ever learned about the Roman Empire in school, you probably picture togas, gladiators fighting lions in packed arenas, and emperors like Julius Caesar who got stabbed by his friends. You might have also learned that the Roman Empire “fell” in 476 CE, when the last emperor in the west was kicked out of power by a barbarian general. But what if I told you that half the Roman Empire didn’t fall at all? That half kept going for another 1,000 years, built a capital city that was the most beautiful, richest, most defended city in the world for a millennium, and survived invasions, plagues, religious fights, and even 50 years of being split into tiny separate pieces by enemies? That empire is the one we now call the Byzantine Empire—but the people who lived there would have been very confused if you called them that. Let’s start with the most basic question: what even is the Byzantine Empire, anyway?

To understand the Byzantine Empire, we first have to rewind to the original Roman Empire, the one you might have learned about already. At its biggest, in 117 CE under Emperor Trajan, the Roman Empire was enormous: it stretched from the rainy hills of Scotland in the north, all the way down to the hot deserts of Egypt in the south, west to the Atlantic Ocean, and east to the borders of modern-day Iran. If you tried to drive from one end of the empire to the other in a car, it would take you about 2 weeks of nonstop driving. It had 70 million people living in it, which was 1 out of every 5 people on the entire planet at the time. The Romans called the Mediterranean Sea *Mare Nostrum*, which means “Our Sea,” because they controlled every single coast around it, and no pirates or enemy navies could sail on it without their permission. For hundreds of years, the Roman Empire was the most powerful, richest, most advanced civilization in the Western world.

But by the 200s CE, the empire was starting to have big problems. It was just too big to rule from one single capital city, Rome. Imagine if the president of the United States had to run the entire country, plus all of Europe, the Middle East, and North Africa, all at the same time, with no phones, no internet, no planes, only horses and wooden ships to send messages. If an invasion happened on the border with Persia (modern-day Iran), it would take 2 weeks for the message to get from Rome to the border, and another 2 weeks for the army to march there. By the time the emperor sent help, the invaders would have already burned down half the farms and stolen all the treasure. Emperors started splitting the empire into two halves: a western half ruled from Rome, and an eastern half ruled from a temporary capital in the city of Nicomedia (modern-day Turkey). This split made it easier to react to invasions and run the huge empire.

The final split happened in 330 CE, when Emperor Constantine I made a decision that would change history forever: he built a brand-new capital city for the eastern half of the empire, on the site of an old, tiny Greek colony called Byzantium. Constantine didn’t pick this spot by accident. Byzantium was located on a narrow peninsula, surrounded by water on three sides: the Bosphorus Strait to the north, the natural harbor called the Golden Horn to the west, and the Sea of Marmara to the south. There was only one side of the city that was on land, which meant defenders only had to guard one set of walls, instead of four. The Bosphorus Strait was also the only waterway that connected the Black Sea (full of grain, fish, and trade ships from Russia and Ukraine) to the Mediterranean Sea, so every single ship that wanted to trade between those two seas had to pass right by the city. Constantine knew that if he built his capital there, he could charge taxes on every single ship that passed through, making the city and the empire incredibly rich.

Constantine spent 6 years building the new city, and he copied all the best parts of Rome to make it feel like home for people moving from the west. He built a massive forum (public square) just like the one in Rome, public baths that were free for everyone to use, an aqueduct that brought fresh water from 100 kilometers away (so people didn’t have to drink dirty river water), a Senate house, and even a massive sports stadium called the Hippodrome, where people could watch chariot races and other events. He also moved famous statues and monuments from Rome to the new city, to make it look as impressive as the old capital. When he was finished, he named the city Constantinople, which means

Constantine spent 6 years building the new city, and he copied all the best parts of Rome to make it feel like home for people moving from the west. He built a massive forum (public square) just like the one in Rome, public baths that were free for everyone to use, an aqueduct that brought fresh water from 100 kilometers away (so people didn’t have to drink dirty river water), a Senate house, and even a massive sports stadium called the Hippodrome, where people could watch chariot races and other events. He also moved famous statues and monuments from Rome to the new city, to make it look as impressive as the old capital. When he was finished, he named the city Constantinople, which means “City of Constantine” in Latin—his own personal tribute to himself, basically the ancient equivalent of naming a new town “Trumpville” or “Taylor Swift City.” On November 11, 330 CE, he threw a huge 40-day party to celebrate the city’s opening, with free food, games, and shows for every single person who lived there, from rich senators to poor street vendors.

At first, Constantinople was just the capital of the eastern half of the Roman Empire, which still thought of itself as one single empire split into two parts for easier ruling. The final split happened in 395 CE, when Emperor Theodosius I died and left the empire to his two sons: the older son Arcadius got the eastern half (with Constantinople as its capital), and the younger son Honorius got the western half (with Rome as its capital). For a long time, both halves still called themselves “the Roman Empire,” and they even helped each other when invaders attacked. But the western half was in much worse shape: it had more invasions from Germanic tribes like the Goths and Vandals, its farms were destroyed, its treasury was empty, and its capital Rome was getting smaller and poorer every year.

In 476 CE, the final blow came to the western half: a Germanic general named Odoacer kicked out the last western Roman emperor, a 16-year-old boy named Romulus Augustulus. But here’s the part most school textbooks skip: Odoacer didn’t declare himself emperor. Instead, he sent the western imperial crown to the eastern Roman emperor in Constantinople, and told him the west no longer had a ruler, so the east was now the only Roman Empire left. The eastern emperor accepted the crown, and from the perspective of people living in Constantinople, the Roman Empire never “fell” at all—they just lost control of the western lands for a while, which they planned to take back later. And they were right: for the next 1000 years, the empire based in Constantinople would keep calling itself the Roman Empire, and its citizens called themselves Romans.

So wait—if they called themselves Romans, why do we call them the Byzantine Empire? The name “Byzantine” is actually a made-up label that didn’t exist until 1,000 years after the empire was founded. The site of Constantinople was originally a tiny ancient Greek colony called Byzantium, founded around 657 BCE by colonists from the Greek city of Megara. For more than 1,000 years, it was just a small, unimportant fishing town, until Constantine decided to build his capital there. In the 1500s, a German historian named Hieronymus Wolf[^1] was translating and editing old Greek historical manuscripts from this empire, and he needed a way to tell them apart from the old western Roman Empire that had fall