At that time people in the Souvr'n reaches off Caledonia were not different ~
Now, to add some mystery and intrigue into this, they had, by that time, some marker genes from India suggesting that ancient Dravidians or Indo Europeans on their way to the ends of the Earth ended up here. Might find some Hindu religious signs on that same statue if you look real close.
So, gang, hep' me out ~ that Caracalla fellow has an interesting name ~ car a calla or the clearly Gaellic "Ker Ak Alla" ~ a sentence having something to do with HOUSE OF ALLA or HOUSE OF WALLA ~ or maybe it was "KER A KAL LA" which means something like House of the Conqueror of the Kal country was he even Italian, or was he another guy like Constantine ~ from Wales?
What about the Celts in China? I believe the first tartans started there,
There are two branches of Celtic: P-Celtic and Q-Celtic. Q-Celtic includes the language of the ancient inhabitants of Ireland and those speaking a language derived from it--Irish Gaelic, Scottish Gaelic, and the recently-extinct Manx. P-Celtic is everything else, including the language of ancient Gaul and the language of ancient England and the languages descended from it (Welsh and Breton). Some of the placenames in southern Scotland are P-Celtic so a language of the P-Celtic variety must have been spoken there before Gaelic was introduced from Ireland.
I don't know how Pictish fits into the picture. Apparently there are some very old place names in the British Isles which are Indo-European but not Celtic. Of course there were people in the British Isles long before the Celtic language reached them--the people who built Stonehenge did not speak Celtic.