Once he was a Celtic warrior, or so Stewart Campbell thought until his latest major project indicated that there is no such thing.

Exactly 20 years ago, in a much more successful era, the then lock forward was part of the last Scottish team to contest a Grand Slam decider – they had done so the previous season too – and beating Ireland in the annual battle of the Celts was something that was pretty much taken for granted.

That team was the first of the professionals to contest a championship tournament, the sport having gone open after the 1995 World Cup, at the start of a process that has transformed the sport.

Campbell, one of an elite group with a winning record for Scotland in the course of a career which also included a victory in Paris - would go on to have a decent career as a professional, playing initially for Dundee HSFP and Caledonian Reds which morphed into Glasgow Caledonians before having spells with Treviso, Leeds and finally, for a few weeks as cover for none other than Martin Johnson while the England captain was engaged in other business in the autumn of 2003, at Leicester Tigers.

A qualified architect he came out of it with little in the bank, but enough to pursue his dream of setting up a film production company and Tigershark Ltd was born.

Among his most regular clients is The National Museum for Scotland and that aforementioned project is what has raised this doubt about what these clashes between Scotland and Ireland represent.

The thrust of the exhibition ‘Celts – art and identity,’ which Campbell invited me to take a look at this week and includes 20 films his company has produced, is an examination of who the peoples branded as Celts were and it essentially concludes that there was no such thing, our imagining of them dependent on a sentimentalised Victorian re-interpretation of Greco-Roman histories.

As an aside, amid the relentless jibes about ‘the new Rangers’ in recent years, it was odd, too to discover an almost precise correlation between that fictionalisation and the period that Brother Walfrid was setting up his version of Celts.

It is a fascinating exhibition, brought to life by his beautifully crafted work, but for Campbell that questioning of whether we are entitled to view ourselves as part of a wider Celtic family is an amusing curiosity, far removed from the more serious concerns he has about the way professional sportsmen define themselves and how they cope when careers end, admitting that it was a troubling time when it was his turn.

“It’s difficult when you finish playing and hang up your boots, there is a definite loss of identity,” he observed.

“Rather than being Stewart Campbell the rugby player, you are just Stewart Campbell and that can be a worry.

“Thankfully the guys in my day had either a trade or profession to fall back on, so the transition was not so bad, but if, as a modern professional player, that is all you have or are, then it can be quite a daunting prospect from a mental wellbeing perspective when that goes.

“I sincerely hope this is being addressed with all the professional players. It does not take much to end a rugby career.”

His take on that is all the more refreshing because Campbell and his contemporaries who were so much more successful than their modern day counterparts, could easily be resentful on discovering that players like Richie Gray, one of his Scotland second-row successors, is set to earn so much money when he moves to Toulouse that he may not need to work again when his rugby career is over.

Instead there is a recognition that the sport is very different compared to those days when it was evolving from amateurism.

“It’s a difficult one trying to put yourself in the modern players’ shoes. To begin with I think Richie Gray’s feet are two sizes too big for me,” he joked.

“The power and physique of the players has evolved since I finished playing and the game itself has moved on, much more defence orientated.

“You have to really play the cards you are dealt, so I think the players are worth whatever they can get contract-wise, good on them. I instinctively believe, though, that the effort that goes in at training and on game day does not relate to how much an individual is getting paid. I don’t think they will be a professional player for long it that was the case.”

Whether they are confronting Celtic brothers or are merely Scots getting set to do battle with unrelated opposition from overseas, then, Campbell has fellow feeling with the men who seeking to bridge the gap to that aforementioned 1996 campaign and the last time Scotland won three championship matches in succession.

“I think it’s great that they’ve got back to back wins. Here’s hoping they can get another against Ireland,” he said.

Should they do so it might not yet be the stuff that legends are made of, but Celts or no Celts they have the current squad has a chance to start re-writing sporting history in a way that will look more favourably upon the efforts of Scottish rugby than it has for most of the past two decades.