Celtic Irish settlers, in what is now Scotland. In the early 6th century ad they settled Argyll (Ar Gael) after two centuries of raiding the coasts of Britain and Gaul. They overcame the northern Picts in the Highlands and introduced the Celtic Gaelic language. The name ‘Scotia’ (Scotland), formerly a name for Hibernia (Ireland) passed to the land of Caledonia and the territories of all the Picts.