Who Was the Greatest Byzantine Emperor? It’s Complicated

Choosing the greatest Byzantine Emperor of all time is a tricky task. We take a look through a handful of the most likely contenders.

Feb 1, 2023By Vedran Bileta, MA in Late Antique, Byzantine, and Early Modern History, BA in History


If you thought defining the greatest Roman emperor was hard, choosing the greatest Byzantine emperor is even more complicated, for one simple reason. There was no Byzantine Empire. In fact, the term “Byzantine” appeared for the first time almost a century after the fall of Constantinople in 1453. What we call “Byzantine” is nothing other than the Roman Empire, the same one founded by Emperor Augustus. After all, the “Byzantines” called themselves “Rhomaoi” or “the Romans.” And they knew their empire as “Basileia ton Rhomaion” or “the Empire of the Romans.” But, if we have to choose the greatest Byzantine emperor, each of those four men would fit the category.


Justinian I – One of the Greatest Byzantine Emperors

byzantine emperor justinian mosaic
The detail of the mosaic showing the emperor Justinian I, 6th century CE, Basilica di San Vitale, Ravenna, via Historytoday.com


Justinian I (527-565) is an excellent case of why it is difficult to talk about the greatest Byzantine emperors. First and foremost, Justinian should fit perfectly into the “Roman emperors” category. After all, he was the one who (with the help of talented general Belisarius) brought Africa and Italy back under imperial control. Justinian’s reconquest, however, overextended the Empire’s limited resources, making it hard for Justinian’s successors to defend the vast territory.


It did not help that amid the Italian campaign, a deadly plague struck the Roman Empire, ruining its economy and weakening its military. Following the Nika riot that damaged most of the capital, Justinian rebuilt Constantinople, embellishing it with monumental architecture; Hagia Sophia being the most famous. Justinian did not rule alone. His co-ruler and closest ally was his wife, empress Theodora. The empress played a critical role in shaping religious policy and preserving religious unity, one of the main pillars of the mighty Christian state.


Heraclius – Savior of the Empire

heraclius emperor coin
Golden coin showing emperor Heraclius with his son Heraclius Constantine (obverse), and the True Cross (reverse), 610-641 CE, via The British Museum


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Emperor Heraclius (640-641) took the throne at a time when the Empire was facing certain destruction. Heraclius’ most dangerous enemy was the Sassanian Empire, which invaded the imperial territory, taking all of the eastern provinces. Personally leading the imperial armies, Heraclius managed not only to defend the Empire but to beat Sassanids on their home turf. His triumphant return of the True Cross to Jerusalem marked the end of the final Roman-Persian war, also known as “The Last Great War of Antiquity.” 


Unfortunately, the annihilation of the Roman field army at Yarmuk in 636 and the subsequent loss of all of the eastern provinces to the forces of Islam annulled all Heraclius’ gains, ending his reign on a rather bitter note. However, Heraclius’ reforms, and reorganization of the army, gave his successors a fighting chance, and the Roman Empire gradually transformed into a smaller but still powerful medieval state.


Basil II – The Warrior Emperor

byzantine emperor basil II icon
Emperor Basil II, shown crowned by Christ and his angels, and flanked by six military saints. Courtiers and defeated enemies bow at the emperor’s feet. Replica of the Psalter of Basil II (Psalter of Venice), BNM, Ms. gr. 17, fol. 3r, Biblioteca Nazionale Marciana, Venice, via Byzantium-blogger.blog


Emperor Basil II (976 – 1025) was a member of the renowned Macedonian dynasty, which restored imperial fortunes, making the Byzantine Empire the most powerful state in the medieval Mediterranean. After taking the purple, Basil would rule for more than half a century, relentlessly fighting numerous enemies of the Empire, becoming a true soldier emperor. However, Basil’s most significant military achievement was the complete subjugation of the mighty Bulgarian Empire. In 1014, after decades of fighting, the imperial army won a decisive victory at the Battle of Kleidon.


For the first time since the 7th century, the Danube frontier was under imperial control, together with the entire Balkan peninsula. However, the epithet Boulgaroktonos (the Bulgar Slayer) was a later invention used by the imperial propaganda to highlight Basil’s martial exploits over the weaknesses of his successors. By the end of Basil’s life, his Empire stretched from Southern Italy to Armenia and Syria. Emperor Basil, unfortunately, left no heir, and his work was quickly undone by his weak and incompetent successors.


Alexios I Komnenos: The Byzantine Emperor Who Founded the Last Great Imperial Dynasty

byzantine emperor alexios komnenos
Alexius I Comnenus, Byzantine emperor (r. 1081–1118), detail of an illumination from a Greek manuscript; Vatican Library (Cod. Vat. Gr. 666), via thoughtco.com


Byzantine Emperor Alexios I Komnenos (1081–1118) ascended the throne at the moment of great upheaval in the Byzantine Empire, threatened by the Seljuk Turks on one side and the Normans on the other. Alexios managed to defeat the Normans, but his forces were inadequate to fight the Seljuks in Anatolia. Hoping for several contingents of elite knights, the emperor appealed to the West for help. Instead, he got the First Crusade.


A great diplomat, Alexius made the most of this troubling situation, regaining some lost territories with the help of the Crusaders, including Nicaea and much of the Anatolian coastline. Alexios’ successors – emperors of the Komnenian dynasty – continued the war against the Seljuks but could not expel the enemy from Anatolia. To make matters worse, the Crusades gradually undermined the Byzantine power, and in 1204 Constantinople fell to the Latins. From then onwards, the Empire was only a shadow of its former self until 1453, when the Ottoman Turks conquered Constantinople, bringing the thousands-year-old Roman empire to an end. 

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By Vedran BiletaMA in Late Antique, Byzantine, and Early Modern History, BA in HistoryVedran is a doctoral researcher, based in Budapest. His main interest is Ancient History, in particular the Late Roman period. When not spending time with the military elites of the Late Roman West, he is sharing his passion for history with those willing to listen. In his free time, Vedran is wargaming and discussing Star Trek.