Dating practices in other countries
Dates associated with the Celts in their movement into the Balkans are 335 BC, when Alexander the Great received delegations of Celts living near the Adriatic, and 279, when Celts sacked Delphi in Greece but suffered defeat at the hands of the Aetolians.
In the following year, three Celtic tribes crossed the Bosporus into Anatolia and created widespread havoc.
There is no doubt that, during this period, many Celtic tribes, formerly living east of the Rhine, were forced to seek refuge west of the Rhine; and these migrations, as well as further German threats, gave Julius Caesar the opportunity (58 BC) to begin the campaigns that led to the Roman annexation of the whole of Gaul.
The Celtic settlement of Britain and Ireland is deduced mainly from archaeological and linguistic considerations.
Between the 5th and 1st centuries BC the La Tne culture accompanied the migrations of Celtic tribes into Eastern Europe and westward into the British Isles.