## TL;DR

The Byzantine Empire (Eastern Roman Empire, 330-1453 CE) preserved Greco-Roman knowledge through the Middle Ages. Capital: Constantinople (founded 330 by Constantine). Orthodox Christianity, Greek language, Roman law (Justinian's Code, 529). Hagia Sophia (537, world's largest cathedral for 1000 years). Fell to Ottoman Turks (1453).

## Core Explanation

Justinian I (527-565): reconquered much of Western Empire, codified Roman law (Corpus Juris Civilis — basis of European civil law). Iconoclasm (726-843): debate over religious images. Macedonian Renaissance (867-1056): cultural revival. Fourth Crusade (1204): Crusaders sacked Constantinople — empire never fully recovered. Legacy: preserved classical texts that fueled Renaissance.

## Further Reading

- [Byzantium: The Surprising Life of a Medieval Empire (Judith Herrin)](https://press.princeton.edu/books/paperback/9780691143699/byzantium)