Around 513 BC, as part of the military incursions ordered by Darius I, a huge Achaemenid army invaded the Balkans and tried to defeat the Western Scythians roaming to the north of the Danube river.
Several Thracian peoples, and nearly all of the other European regions bordering the Black Sea (including parts of modern-day Bulgaria, Romania, Ukraine and Russia), were conquered by the Achaemenid army before it returned to Asia Minor.
For instance, Megabazus' own son, Bubares, married Amyntas' daughter Gygaea,[3] with the intention of ensuring good relations between the Macedonian and Achaemenid rulers and reinforcing the alliance.
Heading towards the Thermaic Gulf, the infantry and the navy encountered difficulties; the former was attacked at night by the Byrgi, while a strong storm devastated the latter.
[13] As Herodotus mentions in his Histories; "and with their army they added the Macedonians to the already existing slaves [of the Persians]; for all the peoples on their side of Macedonia had already been subjected to them".
Some artefacts, excavated at Sindos and Vergina may be considered as influenced by Persian culture, or even imported from Persia in the late sixth and early fifth centuries BC.