 Gallic groups, originating from the various La Tène chiefdoms, began a south-eastern movement into the Balkan peninsula from the 4th century BC.Although Gallic settlements were concentrated in the western half of the Carpathian basin, there were notable incursions, and settlements, within the Balkan peninsula itself.From their new bases in northern Illyria and Pannonia, the Gallic invasions climaxed in the early 3rd century BC, with the invasion of Greece.