How Did the Byzantine Empire Last So Long?

Map of Constantinople during the Middle Ages.

Why the Eastern Roman Empire lasted for so long is a huge question, and the implications of its survival an even broader one. I couldn’t possibly really address both completely in one post. However, this is an important question because the longevity of Constantinople was important for the development of Western Civilization. So, I will attempt to answer it in a sort of broad-strokes fashion.

"Greek Fire" was the Byzantine Navy's secret weapon.

Why the Eastern Empire Was Able to Survive For So Long

The Byzantine State lasted for over a thousand years, which isn’t too shabby. There were several main reasons:

• It had a strong economy
• It always had a very competent military
• It was in a great location.

These three main attributes all interacted with each other and flowed from the Empire’s founding. The Eastern Empire inherited the Roman Empire’s most productive lands and a well-developed system of maritime commerce. The Roman Empire was never particularly renowned for its navy - it was functional and won when it needed to - but the Romans didn't have much competition after it defeated the Carthaginians. The Byzantines, however, focused on its navy and made some advances (such as "Greek fire") that to this day are still not completely understood.

The Arabs took to calling the Mediterranean the “Greek Sea” because of how well the Byzantines used and controlled it. Trade was vital to the Byzantine economy, and it gave the Byzantines an edge over its less-developed neighbors. The Bulgars were warlike, for instance, but did not have the sort of commerce controlled by Constantinople. The capital’s location right at the intersection of all the most important trade routes certainly didn’t hurt.

Byzantine society was not static, as many may think. Edward Gibbon in "The Decline and Fall of the Roman Empire" paints a picture of a society in constant decline, anchored to old ways of doing things that became increasingly archaic and irrelevant. That may have been true for some periods of Byzantine history, but not all. For instance, Emperor Heraclius, who reigned from 610-641 A.D., for instance, instituted reforms such as the Themes that reinvigorated the Byzantine state. Emperor Basil II (976-1025) instituted popular tax reforms that marked a high point in Byzantine fortunes. 

Emperor Michael VIII is a prime example of the regenerative powers of Byzantine society. After the Fourth Crusade in 1204 fragmented Byzantine society by taking Constantinople, which easily could have been the end of the road. However, Byzantines persevered in secondary power centers, holding off both the Arabs and the Latins while they rebuilt their strength. Michael in 1261 finally put the necessary pieces together to mount a comeback and retake Constantinople. This enabled the Empire to survive as a unified whole for another 200 years. The Byzantines kept reinventing themselves and adapting to changing circumstances right up to the end.

Basil II, who reigned from 10 January 976 – 15 December 1025.

The Byzantine military is constantly underrated by casual observers. The Byzantines inherited the Roman military structures and strategies and enhanced them. Military strategy was always considered of utmost importance and was a favorite topic of the emperors themselves. Emperor Maurice published the Strategikon, Leo the Wise published The Problemata and the Tactica, and Basil II oversaw The Tactica of Nikephoros Ouranos. These were all instructional manuals for the military, showing how much importance the government placed on military science.

In fact, the Byzantines came very near to being obsessed with the military, particularly during the age of the Comneni, but it paid off. The military, despite countless defeats along the way which have given the Byzantine military a poorer reputation than it deserves, sustained the Byzantine State through continual crises and even produced a renaissance in Byzantine fortunes from around 900–1050 A.D.

The Varangian Guard was representative of the very high standard of the Byzantine military. It was formed as a personal guard for the Byzantine emperor Basil in the 9th Century (formally, in the late 10th Century). It was comprised of Norse mercenaries, many of them Swedish. There is ample historical evidence of their presence and origin, including the "Greek Runestones” carved in the 11th Century that can still be seen today on the balcony of the Haghia Sophia in Istanbul. These Greek Runestones were epitaphs of the Norsemen who went to Greece.

Constantinople, at the extreme left of this map of ancient trade routes, was the western terminus of a vast network that extended to the Pacific and Indian Oceans.

The Eastern Empire was in a fantastic location that has hosted empires throughout the millennia. Among other things, it was a major crossroads for trade routes, which provided a steady stream of revenue until the last days of the Empire. Before the Byzantines, Anatolia was the center of the Hittite Empire, then it formed a huge portion of the Roman Empire, then the Eastern Empire, and finally the Ottoman Empire. It’s just a great location for defensive purposes and, at least in the past, was considered hugely productive economically. Constantinople itself was a superb defensive spot, and it was fortified with the accumulated wisdom of a millennium of Roman ideas and techniques. It had everything - food, freshwater, the most imposing walls (the Theodosian Walls) of the middle ages. Only when the technology of its enemies finally caught up with it did the Byzantine State enter a period of crisis, and even then it lasted for another 250 years.

There was a high sense of justice in the Byzantine Ages that was unusual enough for the age to be recorded for posterity. In this illustration from the Skylitzes Chronicles, a Thracian woman kills a Varangian who had tried to rape her (left). Afterward, his fellow soldiers praised her and allowed her to have his possessions.{Bibliotica Nacional de Espana}.

Implications of the Survival of the Eastern Empire

As for the implications of the survival of the Eastern Empire, it served as a sort of lifeboat for classical civilization. Roman law continued and developed much further. Life could continue as always for Romans who left the Western Empire and relocated to the fertile East. This enabled a continued evolution of classical civilization that the Byzantines could bestow upon surrounding regions. It was widely understood throughout the Middle Ages that the Byzantine Empire stood head and shoulders above rougher states which surrounded it. That is why, for instance, Scandinavians came down to learn from the Byzantines. Eastern Roman academics spread out as time went on and educated people in surrounding areas. They were especially successful at converting neighboring regions to the Eastern Orthodox religion, which remains a dominant force in Russia to this day because of Byzantine proselytizers.

The construction methods used in the Haghia Sophia (Church of the Holy Wisdom), completed during the reign of Justinian, represented the apotheosis of Roman construction methods.

It’s not as if the Western Roman Empire did nothing in this regard, of course. While Rome “fell,” its influence also continued throughout the middle ages. Building methods certainly did not advance after Rome's fall, however, in the lands taken over by the infiltrating tribes. Roman building techniques matured only in Constantinople, where artisans had adequate protection and patronage, resulting in advances even beyond the Roman architecture in monumental structures such as the Hagia Sofia. Byzantine art also flourished and is one of many sources for the eventual Renaissance in Italy. The Byzantines also established new administrative techniques, such as the development of the themes, that continue to this day in the form if not substance in such government entitles as “states” and “counties.”

The Byzantines preserved literature and artwork from the classical era. Many of the most revered monuments in Venice, for instance, came directly from Constantinople, including the Quadriga in St. Mark’s Place. The timing of the sack of Constantinople in 1204 by the “Crusaders” and the development of the Italian Renaissance immediately thereafter is probably not a coincidence. Having the masterworks of antiquity to review and build upon was a massive contribution to European development from 1200–1500.

The unsuccessful 717-718 siege of Constantinople was one of several times that the city stood directly in the way of assaults on Europe from the southeast.

The Byzantine military also did more than just preserve the Eastern Empire. It served as a sturdy roadblock for aggressive powers in the East. These included the aging Persian Empire, the Arabs expanding at the time of Mohammed, and the growing Ottoman Empire. The Byzantines protected Europe’s flank for a thousand years. Stymied, the Arabs were forced to try end-runs around the Byzantine Empire, such as expanding along the southern Mediterranean coast and then entering Europe through Spain. However, these adventures attenuated their power and proved unsuccessful. Though they finally bypassed Constantinople in the 1300s, the Ottomans couldn’t generate a strong thrust into Eastern Europe until they consolidated their power at the Greek capital after 1453. This gave Western European powers time to develop and finally unite when the Turks reached Vienna and turn them back. History could have turned out much differently without the Byzantines standing guard on the Bosphorus.

The ancient streets of Istanbul helped to save Western civilization (author's photo).

2021