Byzantine Empire

The Byzantine Empire is the modern name for the eastern half of the Roman Empire, which survived the fall of the western provinces in 476 CE and endured for roughly another thousand years from its capital at Constantinople (modern Istanbul). Its inhabitants did not call themselves "Byzantines" — they identified as Rhōmaîoi (Romans) and saw their state as the unbroken continuation of Rome. The label "Byzantine" was popularized by the 16th-century historian Hieronymus Wolf, derived from Byzantion, the Greek colony that preceded Constantinople.

Historians typically date the empire from the founding of Constantinople by Constantine I in 330 CE, or alternatively from the death of Theodosius I in 395, which permanently split Roman administration between east and west. Under Justinian I (r. 527–565), the empire briefly reconquered Italy, North Africa, and parts of Spain, and produced the Corpus Juris Civilis, a codification of Roman law that became the foundation of most continental European legal systems.

Key features relevant to IR and political research:

• Caesaropapism: the emperor exercised authority over both state and church, a model distinct from the western papal–imperial division.
• Orthodox Christianity: the 1054 Great Schism formalized the split with the Latin Church, shaping the religious geography of eastern Europe.
• Diplomacy and statecraft: Byzantine practice — resident envoys, ceremonial protocol, tribute, and playing rivals against one another — heavily influenced later European diplomatic norms.
• Cultural transmission: Byzantine scholars and manuscripts fleeing west after 1453 contributed to the Italian Renaissance; missionaries Cyril and Methodius spread literacy and Orthodoxy to the Slavs.

The empire was gravely weakened by the Fourth Crusade's sack of Constantinople in 1204, partially restored in 1261 under the Palaiologos dynasty, and finally extinguished when Sultan Mehmed II captured Constantinople on 29 May 1453. Its legacy persists in Orthodox Christianity, Roman law traditions, and the political imagination of successor states from Russia (the "Third Rome") to modern Greece and Turkey.