Greece had experienced a raid in Macedonia in 479 and another in 482 by the Ostrogoths under their king, Theodoric the Great.

The Bulgars in 540 and on repeated other occasions had raided Thrace and the rest of northern Greece.

These continuing Bulgar incursions had required the Empire to protect Constantinople by building the "Anastasian Wall," which extends for some thirty miles, or more, from the city of Selymbria (now Silivri) to the Black Sea.

There is no such protection, however, for the provinces in front of the walls.

The Huns and Bulgars in 559 had raided Greece until the imperial army returned from Italy, where Justinian I had been attempting to capture the heart of the Roman Empire.

The Slavs, alone or in association with the Kutrigur Bulgars, have steadily occupied imperial lands in the Balkan peninsula in the fifty years since their initial occupation of lands south of the Danube.

Already a presence in Thrace, Macedonia, Epirus, and Thessaly, the Slavs have by 578 penetrated as far as Achaea in the Peloponnese.