Excerpts from Books and Wikipedia
The chronology of the Medieval Balkans includes: Slavs invade and settle (6th-7th century; Bulgars accept Christianity (865); Battle of Manzikert in 1071 in which Seljuks conquer Anatolia; Constantinople sacked in the Fourth Crusade; and Mongols defeat Seljuk Turks (1243). [Mazower: Balkans: A Short History, Kindle, Location, 34-2803] "In 634 the Muslims marched into Roman Syria, defeating Heraclius's brother Theodore. Within a short period of time, the Arabs conquered Mesopotamia, Armenia and Egypt. Heraclius entered diplomatic relations with the Croats and Serbs in the Balkans." Heraclius was Emperor of the Byzantine Empire from 610 to 641. [Wikipedia] The Ottoman Turks first appeared in the Balkans in 1345. [Wachtel: Balkans in World History, Kindle, Location 1601-1850]
Byzantine Dark Ages follows defeat of Heraclius by Muslims
Culture
641
First Bulgarian Empire established in treaty with Byzantine Empire
Geography
681
Byzantine and Arab armies meet south of Black Sea at Battle of Sebastopolis
War
694
Bulgars become major power located between Charlemagne & Byzantine Empires
Geography
803
Cyril & Methodius are missionaries to Serbia (863), Hungary (864), & Kiev (875)
Religion
863
Byzantines lose Balkans to Bulgaria in Battle of Anchialus
War
917
Basil II, the Bulgar Slayer, has Bulgarian prisoners blinded after battle
War
1015
Croatia and Hungary form union of two kingdoms united under Hungarian king
Government
1102
Manuel victorious against Hungary, but Serbia (Stefan Nemanja) gains independence
War
1161
Bulgarian Empire reestablished after the Uprising of Asen and Peter
War
1185
Bulgarians under Emperor Kaloyan defeat Baldwin I at Battle of Adrianople
War
1205