Eight Key Facts About the Byzantine Empire

Remains of the Theodosian Walls in Istanbul (author's photo).

The Byzantine Empire is famous for being the only government west of China to survive intact from ancient to medieval times. Its capture in 1453 became one of the defining moments of the Middle Ages. However, many basic facts about the Empire are not well known. Here, we present eight key facts about the Byzantine Empire that everyone interested in the topic should know.

1. Why Do We Call the Eastern Roman Empire the Byzantine Empire?

Not everybody likes the term "Byzantine Empire," considering it inaccurate in its description of the late Roman Empire. However, there is a clear historical reason for using it.

With events as ancient as the founding of Byzantium, there almost inevitably are elements of both fact and myth mixed into the "history." Below is the commonly accepted genesis of the name Byzantium. The more you study ancient history, though, the more you find that there are variations in these types of "facts" depending on what sources you follow and there is no "one story."

In 667 B.C., a man called Byzas founded a small Greek colony on the European side of the Bosporus (the strait linking the Black Sea to the Mediterranean). Byzas was the son of King Nisos of the Dorian city-state Megara, a municipality in West Attica, Greece, in the general vicinity of Athens. According to legend, the oracle of Delphi suggested to King Nisos that he send his son in search of "the land opposite the city of the blind." Byzas chose the spot because the people of Chalcedon, located directly across the Bosphorus, had not settled in that spot despite its proximity and thus were blind to its possibilities.

Byzas named his new city Byzantion after himself. Over time, this name was corrupted to Byzantium. This location became increasingly important with time because it served as a transit and trade point between Europe and Asia. This trade grew steadily over the centuries. 

In 324 A.D., Roman Emperor Constantine, often called Constantine the Great, chose Byzantium as the site of "New Rome." He renamed Byzantium Constantinople (Kōnstantinoupolis, or the City of Constantine) after himself. The city was formally designated as Constantine's new capital on 11 May 330. In practice, this divided the classical Roman Empire in half, as henceforth there were two thrones and two Emperors, one in Rome and the other in Constantinople. These two separate empires theoretically were equals and operated more or less in harmony.  However, in practice, they increasingly operated independently until the Western Empire, as it became known, was overrun and conquered during the Fifth Century.

Some scholars don't like to use the term Byzantine Empire. They feel the more accurate term is "Eastern Roman Empire." While some people are emotionally invested in emphasizing that the Byzantine Empire actually was a continuation of the Roman Empire, and the citizens of that empire always considered themselves Romans, the terms "Byzantine Empire" and "Eastern Roman Empire" really are interchangeable in modern usage and both are considered acceptable in virtually all academic circles.

Stylistically, I prefer to use "Byzantine Empire" because it helps to give this offshoot of the ancient Roman Empire, which over time developed new institutions and practices, its own identity. In a formal, classical sense, calling it the "Eastern Roman Empire" is more technically accurate. however, everybody understands what you mean when you say "Byzantine Empire" and it is not derogatory so that term serves its purpose.

Statue of Constantine the Great.

2. Why Did Constantine Choose Constantinople as the New Rome?

Constantine was an expert in the economic and military conditions of the western half of the Roman Empire. He saw that it was becoming increasingly vulnerable to attack and that its economy was stagnating. He further recognized that the eastern provinces of the Roman Empire - those located east of the Adriatic - had prospered and had different defensive needs (against the Persians) than the western provinces. Thus, Constantine decided the center of gravity of the Empire had shifted east and the Roman capital should be moved to reflect this geopolitical fact.

We explore the reasons Constantine chose this particular site over others here.

A mosaic in the southwestern entrance to the Haghia Sophia in Istanbul. The Virgin Mary stands in the middle, holding the Christ child on her lap. On her right side (our left) stands emperor Justinian I, offering a model of the Hagia Sophia. On her left, Emperor Constantine I presents a model of the city (author's photo).

3. How Did the Byzantine Empire Adopt Christianity?

Christianity was made the de facto state religion of the Roman Empire by Theodosius the Great. While Constantine the Great decades earlier had issued the Edict of Milan in 313 A.D., it only wanted Christians religious toleration. Paganism remained the faith of a large proportion of the population and experienced a brief revival during the reign of Emperor Julian (361 - 363). On 27 February 380, Theodosius and his co-emperors issued the Edict of Thessalonica (also known as Cunctos populous). This finally made Nicene Christianity the state religion of the Roman Empire. Paganism quickly died out (Theodosius dissolved the order of the Vestal Virgins and allowed Christians to persecute Pagans) and Christian heretics increasingly were persecuted.

Theodosius has a feast day of 17 January (the date of his death in 395) in the Catholic, Eastern Orthodox, and Oriental Orthodox churches due to his support of Christianity.

A Byzantine coin (Solidus) depicting Theodosius the Great.

4. When Did Byzantium Become Its Own Separate Empire?

While Constantine the Great established Constantinople as the New Rome in 330 A.D., that did not create a new empire. It was still one Roman empire, simply divided for administration purposes. The real, permanent separation of Byzantium into its own, independent empire took place in 395 A.D.

Theodosius I (also called Theodosius the Great), the Roman Emperor as 395 began (he died in January), was the last man to rule both halves of the Empire. He did this from Constantinople. Upon his death in 395, the Empire formally was divided between his sons Arcadius (East) and Honorius (West). Before he died, Theodosius commissioned the great walls that protected the city for over a millennium, the Golden Gate in those walls (after which the Golden Gate Bridge in California is named), and numerous other practical structures. Theodosius more than Constantine was the true architect of the Byzantine Empire.

Justinian has become perhaps the most famous Byzantine Emperor, but there were 93 other Emperors.

5. How Many Byzantine Emperors Were There?

There were 94 Byzantine Emperors, beginning with Constantine the Great. This number includes Empresses. There were nine times when co-Emperors served at the same time, though five of these instances involved one Empress, Zoe, who never served alone.

Empress Zoe ruled through three separate husbands.

6. How Many Empresses Ruled Byzantium?

The Eastern Roman Empire had three empresses regnant. These were Irene of Athens (April 797–31 October 802), Zoë Porphyrogenita (15 November 1028 –June 1050), and Theodora, Zoe's sister (19 April 1042 – after 31 August 1056). Of these, only Irene and Theodora ruled without having a co-Emperor, and Theodora only for about one year. However, there was no question that each of these ladies actually ruled the Byzantine Empire and were the ones with real power at some point in their reigns.

The true standout was Irene. She had an outsized and lasting influence on world affairs despite her brief official reign, though most of it was indirect. Before her actual reign as Empress, Irene served as regent. She thus was the actual ruler far longer than her reign would indicate, off-and-on from 780 onward. She defied convention and even occasionally styled herself "basileus," or emperor, rather than "basilissa," or empress. Needless to say, this was highly unusual, even unique.

The Latins closely monitored events in the Eastern Roman Empire despite its lack of power in Western Europe because Constantinople retained a great deal of moral and spiritual legitimacy (and this was before the Great Schism, so technically the Byzantine Emperor was still the Pope's boss). They were incensed that a woman was acting as emperor and thus considered the throne vacant. This may have contributed to Pope Leo III's decision to crown Charlemagne as "Augustus," or  Western Emperor, on Christmas Day 800. This flagrant slap at Constantinople inflamed tensions. The coronation began the Holy Roman Empire or First Reich. This Reich would last for a thousand years, long outlive the Byzantine Empire, and be considered a precedent by Adolf Hitler and his Third Reich.

Constantine XI Dragases Palaiologos, the last Emperor of Byzantium.

7. Who Were the First and Last Byzantine Emperors?

Constantine the Great is considered the first Byzantine Emperor upon establishing New Rome (Constantinople) in 330 A.D. A case can be made that Arcadius, the son of Theodosius, actually was the first ruler of Byzantium as an independent Empire beginning in 395 A.D.

Constantine XI Dragases Palaiologos, named after Constantine the Great, was the last Byzantine Emperor. He ruled from 1449 until the fall of Constantinople in 1453. The exact details of how Constantine XI died are murky, but it is generally accepted that he perished, sword in hand, while helping to defend the city against the Ottoman Turks.

8. When Did the Eastern Empire End?

After a 40-day siege, Muhammed II managed to take Constantinople on 29 May 1453. The Empire died with Roman Emperor Constantine XI, who perished heroically in the fighting. This was a Tuesday, and Tuesdays henceforth have been considered an unlucky day in the Greek Orthodox religion. Some remnants of the Empire survived for a time. Athens held out until 1456, the Morea was taken in 1460, and the final territory under Greek control - the Empire of Trebizond - fell in September 1461. A true Greek will tell you that the Empire never died, it is just resting.

Istanbul (author's photo).

2021