Slavic_migrations_to_the_Balkans First_Bulgarian_Empire

the slavs, of indo-european origin, first mentioned in written sources inhabit territories north of danube in 5th century ad historians agree had arrived earlier. group of slavs came known south slavs divided antes , sclaveni spoke same language. slavic incursions in balkans increased during second half of justinian s reign , while these pillaging raids, large-scale settlement began in 570s , 580s. migration associated arrival of avars settled in plains of pannonia between rivers danube , tisza in 560s subjugating various bulgar , slavic tribes in process.

consumed in bitter wars persian sasanian empire in east, byzantines had little resources confront slavs. slavs came in large numbers , lack of political organisation made difficult stop them because there no political leader defeat in battle , thereby force retreat. wars persia persisted, 610s , 620s saw new , larger migration wave slavs penetrating further south balkans, reaching thessaly, thrace , peloponnese , raiding islands in aegean sea. byzantines held out salonica , number of coastal towns beyond these areas imperial authority in balkans disappeared.