The eastern part of the Roman Empire was notaffected by the invasions which led to the fall of the western partand continued to exist for nearly 1,000 years. Historians use theterm Byzantine Empire to indicate this part of the empire after thefall of the western part. The people in question did not even knowthis term and called their empire Roman Empire. It suffered lossesas well. It lost territories to the Arabs: eastern Libya and Egypt(641-46), Palestine (634-36) and, by 640, Syria. In 1068-71 theSeljuk Turks took over most of Anatolia (present day Turkey).
In Europe, the empire lost part of its landsin the Balkan Peninsula (in south-eastern Europe) to the Slavs. In582 the Avars took over Dalmatia (coastal Croatia). Probably in the610s, the emperor Maurice invited the Croatians to settle there,where they defeated the Avars. In 680 the Bulgarians invaded whatare now Bulgaria and the Republic of Macedonia, and a treaty withthe empire in 681 marked the beginning of the First BulgarianEmpire. In c. 780 the Serbs established the Principality of Serbiain part of what is now Serbia. In 971 the emperor Basil II seizedthe capital Preslav and suppressed a Bulgarian revolt in 1014. In1185 the Bulgarians regained their land and established the SecondBulgarian Empire.
In 1202-04 there was the Fourth Crusade, wherean expedition for Western Europe was meant to reconquer Jerusalem.However, they ended up seizing and sacking Constantinople, thecapital of the empire. The crusaders established the Latin Empirewhich comprised most of Greece and the area in north-westernAnatolia along the shores of the Sea of Marmora This empire lastedfrom 1204 to 1261. It did not manage to take all the lands of theByzantine Empire and three new states were created in theterritories which had not been taken: The Despotate of Epirus (inwestern Greece), the Empire of Nicaea, which comprised theremaining territories in western and northern Turkey which had notbeen conquered by the Seljuk Turks, and the Empire of Trebizond, inthe far northeaster corner of the peninsula of Anatolia andsouthern Crimea. In 1247, the Nicaeans surrounded Constantinople,which fell in 1261. The Byzantine Empire was restored, but Epirusand Trebizond continued as independent Byzantine states.
The Ottoman Turks became a big power and by1324 they captured the empire’s territories in Anatolia (Turkey).In 1387 they captured Thessaloniki, in Greece, which was the secondmost important city in the empire. In 1389 they defeated the Serbsat the Battle of Kosovo, ending Serb power in the region, pavingthe way for their expansion into Europe. In 1444, Murad II defeateda combined Hungarian, Polish, and Wallachian force. By then theByzantine Empire had become confined to the lands aroundConstantinople, which was besieged and conquered in 1453. This citywas turned into the capital of the Ottoman Empire. In 1460 theyconquered the Despotate of the Morea, in the Peloponnese Peninsulaof southern Greece. This was a which was a province of theByzantine Empire which was formed in 1349 when this area waswrested from the Frank crusaders who had conquered it and turned itinto the Principality of Achaea in 1204. In 1461 the Ottomansconquered the Empire of Trebizond and in 1479 they conquered theDespotate of Epirus.