It is widely accepted that the origin of the Celts (in the sense of Celtic-speakers) is probably to be found on the European continent and that they covered a large area in Europe and Asia Minor. Since they lived during the period of Greek and Roman supremacy, many records of the Celts and the places where they dwelled, have been transmitted owing to Greek and Roman authors. Place-names provide a good basis for tracing the 'Celticity' of places and peoples, and as archaeology alone fails to divulge the early history and distribution of Celtic speakers, linguistic research is very relevant. Place-names should be considered as the most widespread linguistic legacy of the earliest Celts, since they occur beyond areas of what belongs to the field of typically so-called 'Celtic' archaeology.