The assembled warbands of the Alamanni frequently crossed the "limes", attacking Germania Superior such that they were almost continually engaged in conflicts with the Roman Empire, whilst Goths attacked across the Danube in battles such as the Battle of Beroa and Battle of Philippopolis in 250 AD and the Battle of Abrittus in 251 AD, and both Goths and Heruli ravaged the Aegean and, later, Greece, Thrace and Macedonia. However, their first major assault deep into Roman territory came in 268 AD. In that year the Romans were forced to denude much of their German frontier of troops in response to a massive invasion by another new Germanic tribal confederacy, the Goths, from the east. The pressure of tribal groups pushing into the Empire was the end result of a chain of migrations with its roots far to the east: Huns from the Russian steppe attacked the Goths, who in turn attacked the Dacians, Alans and Sarmatians at or within Rome's borders. The Goths first appeared in history as a distinct people in this invasion of 268 AD when they swarmed over the Balkan peninsula and overran the Roman provinces of Pannonia and Illyricum and even threatened Italia itself.