The Battle of Thermopylae in 267 is the unsuccessful defense of the pass by local forces during the great invasion of the Balkans by the Heruli.The Heruls are first mentioned by Roman writers in the reign of Gallienus (260-268), when they accompany the Goths ravaging the coasts of the Black Sea and the Aegean.

The mixed warbands manage o sack Byzantium in 267, but their eastern contingent is virtually annihilated in the Balkans at the Battle of Naissus (Serbia) two years later, the battle that earns Marcus Aurelius Claudius his surname "Gothicus."