The End of the Empire
After the capture of Constantinople by Western forces in 1204, members of the court of the defeated Byzantines established bases in Asia Minor. The Byzantines recaptured Constantinople in 1261. But Ottoman Turks soon invaded Asia Minor, and the Serbs advanced in the Balkans. Civil wars also weakened the empire.
By the late 1300's, Constantinople and part of Greece were all that remained of the empire. The empire ended in 1453, when Ottoman Turks captured Constantinople. The last Byzantine emperor, Constantine XI, died while defending the city.
Excerpt adapted from the "Byzantine Empire" article, The World Book Encyclopedia, © 1999