‘Tradition’ as it would be taught by a Latin teacher 
A lot happened between the Romans buggering off and the modern concept of ‘Britain’ emerging, not least the emergence of the concept of the ‘English’ as a people, which could encompass numerous cultures, and indeed nations (according to Ascenray’s definition 
). ‘Great Britain’ as the term we now know dates from the Act of Union.
While I for the most part agree with you, ‘Great Britain’ as the translation for Britannia Major, the island (as opposed to Britannia Minor, Brittany/Bretagne), dates way back – certainly to early Angevin times, probably before that.
But was the 16th century usage picking up on an actual continuous tradition of naming the island thus, or was it a deliberate grab from antiquity to add gravitas to the union? (Genuine question, if phrased badly!)
Some questions, for anyone…
Out of curiosity, how long did “Caledonia” survive as a name for the region? (“Britain/Britannia” seems to have had quite a run so far.) Did anyone besides the Romans use it?
Is the name still used today, if maybe just for panache? Can I root for the “fighting Caledonians” in a school football game somewhere in Scotland? Are there Caledonia Malls to be found in cities? Is there any sentimental or poetic attachment to the name, like what “Albion” is for England?
You’re welcome to support Caley Thistle, if you must. You can also take ferries and a train with the name, but it’s not something you’ll hear in everyday conversation.
A lot of names have the word in them somewhere, particularly in the Scottish highlands. Inverness Caledonian Thistle is a big football club in Scotland; one of the universities in Glasgow is called Glasgow Caledonian University; there’s a Caledonian forest, a rail company called Caledonian railway, the Caledonian Club is the social club for Scottish exiles in London.
It’s not used very often to refer to Scottish people or Scotland though, I’ve never heard it used in everyday language even for poetic ‘panache’ (the same way Erin is used for Ireland in Irish songs, for instance). It might still be used in that way sometimes, I just haven’t heard it myself.
There was a British Caledonian Airways until the 1990s or so.
As well as inside the United Kingdom. I remember hearing Tony Blair refer to “Britain,” meaning the state whose government he led, on more than one occasion.
Personally I think the phrase Britain should be a political rather than a geographical one, taken as referring to all 4 nations including Northern Ireland, just as ‘the UK’ is (I think in practice Britain is usually taken in this way, as referring to the UK the country, not Great Britain the island). After all, citizens of Northern Ireland are called British - why shouldn’t they be considered part of ‘Britain’?
Gah sod it. I’m now officially Mercian.
Well that’s all well and good for you, but what the hell are people from Wessex supposed to call themselves?
West Saxons! He says half a mile from the Mercia/Wessex border!
Wessexians? sounds vaguely pervy, though.
The Scottish word “Sassenach” is derived from the Saxon word “Sassun” – the same word as “Saxon” comes from – so a Scot might call you a Western Sassenach.
Weh-sexxy!
And the Gaelic word for Britain is something like “Sassana”, which I’ve always thought sounds much cooler. It’s like something out of a fantasy novel. I might start using it as part of my address.
[ETA] Correction - Sassana is the Gaelic word for England rather than Britain?
Sassain is England, Alba is Scotland, and Breatainn is Britain (I think) in Scots Gaelic. In Irish Gaelic it’s Sasana, Albain and An Bhreatain. An Bhreatain Bheag is Wales in Irish but I don’t know what it is in Scots Gaelic.
What’s Brittany in Irish? Does “An Bhreatain Bheag” mean “Little Britain”?
Kinda ironic really - the Welsh for English (as a people) is “Saes”, the adjective is “Saesneg” … so now I’ve got an image of all these Jutes and Angles and Freisians etc. moaning about how ignorant the Celts are “Don’t they know we’re not ALL Saxons !!” 
Back to the football thing I was very surprised landing at Edinburgh airport in 2002 to find the majority of people cheering Argentina on against England in the World Cup. My impression, rightly or wrongly, is that Scottish nationalism has actually increased since they’ve had their own parliament.
(Continental) Europeans have a hard time with this too - they talk about “anglo-saxon” culture when talking about English speaking peoples. My Irish husband has a hard time explaining why he would never refer to himself as “anglo-saxon”.
Scotland seems to have done better in the marketing stakes for lack of a better word, you can buy Guide books to Scotland but the guidebook to Angleterre/Inghilterra will include Wales :dubious:
Born in : England
Nationality : British
Passport : United Kingdom of Great Britain and Northern Ireland
Self-Identified : British, if pushed “half-Welsh, half -English”; altho’ I tend to stress the Welsh side more when outside the UK in an attempt to fight England = UK ignorance
(and with my Irish in-laws )
Football : yawn
Rugby : WALES !! then anyone who’s playing an nice open game
Big?
Well I never;)