Sclaveni The name Sclaveni ( , ) was used to describe all Slavic peoples that the Byzantine Empire came into contact with . Terminology . The Byzantines broadly grouped the numerous Slav tribes living in proximity with the Eastern Roman Empire into two groups : the Sklavenoi and the Antes . The Late Roman historians , Jordanes and Procopius both locate the Sklavenoi in the lower Danube ( modern Wallachia and Moldavia ) , although " Sklavi " subsequently in Latin sources in connection to events in Lombard Italy . Whilst there were many Sklaveni , the Antes were a specific ethicon who had a " foedus " with the Byzantine Empire , and were probably located in Scythia Minor . The derived Greek term Sklavinia ( i ) ( , ) was used for the Slav settlements ( area , territory ) which were initially out of Byzantine control and independent . The term may be interpreted as " Slav lands " in Byzantium . However , by 800 , the term also referred specifically to Slavic mobile military colonists who settled as allies within the territories of the Byzantine Empire . Slavic military settlements appeared in the Peloponnese , Asia Minor , and Italy . The Byzantines also referred to the Avar military elite as Sclaveni . These elites re - established their power - base under either Frankish or Byzantine rule in Pannonia and Moravia . History . The Sklavenoi plunder Thrace in 545 . Daurentius ( fl . 577 – 579 ) is the first Slavic chieftain to be recorded by name , by the Byzantine historian Menander Protector , who reported that the Avar khagan Bayan I sent an embassy , asking Daurentius and his Slavs to accept Avar suzerainty and pay tribute , because the Avars knew that the Slavs had amassed great wealth after repeatedly plundering the Byzantine Balkan provinces . Daurentius reportedly retorted that " Others do not conquer our land , we conquer theirs [ . . . ] so it shall always be for us " , and had the envoys slain . Bayan then campaigned ( in 578 ) against Daurentius ' people , with aid from the Byzantines , and set fire to many of their settlements , although this did not stop the Slavic raids deep into the Byzantine Empire . In 577 some 100 , 000 Slavs poured into Thrace and Illyricum , pillaging cities and settling down . By the 580s , as the Slav communities on the Danube became larger and more organised , and as the Avars exerted their influence , raids became larger and resulted in permanent settlement . In 586 AD , as many as 100 , 000 Slav warriors raided Thessaloniki . By 581 , many Slavic tribes had settled the land around Thessaloniki , though never taking the city itself , creating a " Macedonian Sclavinia " . As John of Ephesus tells us in 581 : " the accursed people of the Slavs set out and plundered all of Greece , the regions surrounding Thessalonica , and Thrace , taking many towns and castles , laying waste , burning , pillaging , and seizing the whole country . " However , John exaggerated the intensity of the Slavic incursions since he was influenced by his confinement in Constantinople from 571 up until 579 . Moreover , he perceived the Slavs as God ' s instrument for punishing the persecutors of the Monophysites . By 586 , they managed to raid the western Peloponnese , Attica , Epirus , leaving only the east part of Peloponnese , which was mountainous and inaccessible . The final attempt to restore the northern border was from 591 to 605 , when the end of conflicts with Persia allowed Emperor Maurice to transfer units to the north . However he was deposed after a military revolt in 602 , and the Danubian frontier collapsed one and a half decades later ( " Main article : Maurice ' s Balkan campaigns " ) . Constans II conquered " Sklavinia " in 657 - 658 , " capturing many and subduing " . Constantine III settled captured Slavs in Asia Minor , and in 664 - 665 , 5000 of these joined Abdur Rahman . In 785 , Constantine VI conquers the Sclaviniae of Macedonia ( ' Sclavenias penes Macedoniam ' ) .