When we think of empires, size is often what first comes to mind. Empires are big not only in geographical extent, but in power and number of people, often composed of many different ethnicities. But there are two sides to the coin for being an empire: what outsiders consider a state and what that state considers itself. Despite early reluctance to accept its imperial mantle during the Republic, Romans eventually developed and accepted an idea of themselves as masters of an empire. Its neighbors, however, had long before recognized Rome’s imperialism.
But what of Rome’s successor, the Byzantine Empire? By the time Constantinople fell in 1453, Byzantium was just a shadow of former Roman glory, territory, and might. But until the end, the difference between Rome and Byzantium was that Byzantium had no doubts as to its imperial nature but as time went on, its neighbors did.
The Roman Empire began as the small Roman Republic in 509 BC when it overthrew its king. Over the centuries, it gradually conquered more and more land, first dominating Italy before taking on the great powers of its day, Carthage and the Hellenistic kingdoms. But despite controlling much of the known world by the 1st century BC, Rome was still not comfortable with the idea of empire. It had started by overthrowing a tyrant, and the idea of becoming an authoritarian power itself was somewhat uncomfortable. Roman senators and writers were at pains to justify any wars or territorial acquisitions as necessary to protect Rome.
But, whether by design or by chance, Rome ended up with an empire spanning the entire Mediterranean world. After the Roman Empire began under Augustus, the idea of empire gradually became more and more accepted inside Roman society. However, by this time Rome was not conquering but rather consolidating and ruling. Its accepted imperialism was based in the rule of empire, not in the conquest of empire. By the 3rd century, the Roman Empire was readily acknowledged and asserted by Roman sources.
Rome’s neighbors had seen it as an empire for centuries. For example, the 2nd century BC Greek writer Polybios referred to Rome as an empire back during the time of the Macedonian Wars (214-148 BC). This impression would not change even during the Germanic invasions of the 4th and 5th centuries. Germanic chieftains received titles from the emperor and Attila the Hun even tried to marry the emperor’s sister, Honoria. Although Rome’s strength waned, its imperialism was still recognized.
When the Germanic chief Odoacer extinguished the Western Roman Empire in 476, the Eastern Roman Empire continued at Constantinople. Although today we refer to this empire as the Byzantine Empire, the Byzantines saw themselves as Romans and as a continuation of the Roman Empire. When Emperor Theodosius I (r. 379-395) permanently split the Roman Empire in two he didn’t make one half greater than the other. So while the fall of the Western Roman Empire certainly had some effect, it didn’t destroy the Roman Empire, which survived for another thousand years.
From the start, the Byzantine Empire was not a conquering empire. During its existence, Byzantine armies rarely ventured outside territory that had at one point or another belonged to the Roman Empire. Byzantium could be termed a reconquering empire. Under the early Byzantine emperors, especially Justinian (r. 527-565), a main goal was to reconquer lands that had been lost to the Germanic invaders. In this sense, Byzantine imperialism’s relationship to conquest was about reconquering its Roman legacy, while the Rome was focused on securing and ruling its territories.
The person of the emperor was of supreme importance in Roman imperialism. This included the pagan worship of the emperor as a deity. This changed by the later Roman Empire. In the 4th century, Christianity had become the religion of the Roman Empire. Only one emperor from the time of Constantine I (r. 306-337) onward was not Christian. This trend was carried on and strengthened under the Byzantine Empire. Later Roman and Byzantine emperors did not rule as deities, but they did rule as the anointed representative of God. Although the emperor’s authority was tied to religion, the church was a powerful force with which the emperor had to contend. Unlike during the earlier Roman Empire, the religious and political authority of the empire was no longer vested in one man, but in two. For the Byzantines, this meant that the emperor and the Patriarch of Constantinople, the leading religious figure in Byzantium, to an extent shared power, although the emperor was almost always triumphant whenever any disagreement between the two occurred.
The title of emperor was more contentious during the Byzantine era than the Roman one. Roman emperors had held the title of imperator with no competition from outside powers. They usually referred to foreign monarchs as rex, or king, and the two powers that were in fact honored with the title, the Sassanian Empire in Persia and Axum in Ethiopia, were recognized as equals. The Byzantines continued using the title imperator until Emperor Heraclius (r. 610-641) changed it to the Greek βασιλεύς (Basileus) to match the Hellenization of the empire.
The Byzantines zealously guarded the title of βασιλεύς, not granting it to other Christian powers in Europe. However, Pope Leo III crowned Charlemagne imperator in 800, when Irene sat on the Byzantine throne. Leo considered the Roman throne vacant, since Irene was a woman and had murdered her son, the rightful emperor, to boot. The Byzantines were outraged, but did recognize his title in 812 to avoid a war, shifting their emperor’s title to βασιλεύς Ῥωμαίων, “Emperor of the Romans.” Later Holy Roman Emperors were accorded the title “Emperor of the Franks,” and other foreign powers were given the title of βασιλεύς as well, but the Byzantines did not recognize any other claims to “Emperor of the Romans,” such as those of the Bulgarian Tsar Simeon (r. 893-927) and Stefan IV Dušan (r. 1331-1355).
The Byzantine emperors were especially insulted whenever foreign rulers referred to them as “King of the Greeks,” both denying their empire and their claim to be Roman. This insult became increasingly common from the 12th century onward. For example, Holy Roman Emperor Frederick I Barbarossa (r. 1155-1190) called Byzantine Emperor Manuel I Komnenos (r. 1143-1180) “King of the Greeks” out of a lack of respect.
After Manuel’s reign, the Byzantine Empire deteriorated irreversibly and its prestige depreciated rapidly. Although foreign monarchs still treated with the Byzantine emperors, there was no longer the same amount of awe or respect. Although the Byzantine Empire had certainly declined since 476, it was still deemed a powerful and respectable state through the reign of Manuel. But as the empire’s borders continued to shrink, its prestige floundered and especially after the fall of Constantinople to the 4th Crusade in 1204, Byzantium’s reputation could never recover. Foreign powers came to see the Byzantine Empire more and more as a Greek kingdom, both due to its decreasing size and prestige. The Byzantines would claim to be Romans and their emperors the βασιλεύς Ῥωμαίων until the final fall of Constantinople in 1453 to the Ottoman Turks, but that claim would be based on their former illustrious achievements. Although the Byzantines maintained their imperialism, by the 13th century their empire, at least the sizable multiethnic state that had existed before, was already gone forever.