The different tribes and peoples who lived in different areas of The British Isles during the times of the Roman Invasion had a range of cultural and linguistic differences. Ptolemny's map and tribal list seems to be borne out by History and fairly believable. Many names and features continue with us to this day.
Similarly, the different peoples who made up the four kingdoms which united into Scotland in 843 under Kenneth McAlpin had different languages, traditions and cultures. The Norse ruled Western Isles were returned to Scottish rule in 1266.

Today I'm not sure whether we are so civilised or really integrated.