It wasn’t a label that defined Pat Barker’s Regeneration trilogy, for example, or Ian McEwan’s Atonement. They were seen as literary fiction (not that one book can’t be seen as several things).

But it seems to me that more recently, perhaps since the change in millennium (and that’s a theory I’m making up as I go along) that anything set in the previous century is now seen as historical fiction, and that the boundary is creeping ever closer.

The Historical Novels Review defines it as fiction ‘which is set fifty or more years in the past, and one in which the author is writing from research rather than personal experience.’

And for the sake of classifications for awards or review pages, that’s a useful definition. Importantly, it’s the second part that brings the transition with it.

When I was teaching fiction last year, some of the undergrads wrote what they considered to be historical fiction – set in the 80s. I banned them from using the term for stories set in my lifetime. But it’s true – they were writing about a time they knew only from the music and the fashion, and we had a heated debate as to whether Billy Idol was genuinely punk, because they were judging by hairdo, not cultural impact or motivation. (“Punk!” I scoffed. “He was no more punk than Abba.” And they didn’t even believe me, because their classifications of music are much more sophisticated than those formed around the jukebox of the Duke of Windsor hotel late at night circa 1982. Apparently.)

Then this week, I had the pleasure of listening to Eleanor Catton in conversation at The Wheeler Centre (what was life like without the Wheeler Centre? I don’t remember). Her The Luminaries won the Booker last year, as have several works of historical fiction recently, including Wolf Hall.

She’s a shy but entertaining speaker, and during the evening she came out with some terrific insights, particularly about the influence of children’s books on her life and writing – even today she reads many books written for children.

At one point she said, “I don’t think The Luminaries counts as historical fiction, because I made it all up. Hardly anything in the book really happened.”

Isn’t that interesting?

Is it only historical fiction if it contains historical events?

The Luminaries does: it is set on the Wild West coast of New Zealand’s South Island during the gold rush. It’s set is a real place (Hokitika) during a specific period of time when documented events took place. There was a gold rush, there were shipwrecks, the local prison was built with the forced labour of those it was intended to imprison. It is even written in a style that references the novels of the era – the research process must have been extensive.

The people are all made up and so are the events in the plot. But so are all of mine, with few exceptions.

In fact my most recent experience of writing about someone who really existed was completely different from any other process of writing fiction – in some ways much more difficult.

But it’s true – there is definitely a great deal of historical fiction that focuses on the lives of people who really lived, especially famous people (who are, after all, better documented and therefore most easily researched). Some of the great series in historical fiction set the tone for this, such as Robert Graves’ Claudius the Emperor series or the  Alexander novels of Mary Renault. The Tudors have a publishing industry dedicated to them – but don’t start me on that.

Maybe the focus on key players (or “forgotten” figures, such as Nicola Griffith’s majestic Hild) in history is linked in our minds with the Enlightenment view of history as progress, with the kings and queens and nobles – later presidents and prime ministers – and generals taking individual actions which affected history – with the cult of the individual as history-maker.

During the twentieth century, as social history in its many forms became more accepted, and growing levels of literacy enabled people to record and read about lives like their own, historical fiction became more egalitarian. Rosemary Sutcliff’s great books about post-Roman Britain, for example, were about innocent bystanders finding their way in a wrecked, war-torn world – just like the people of Britain during and after WW2.

Then there are time-slips (my favourite as a kid was Ronald Welch’s The Gauntlet), novels which switch between past and present (AS Byatt’s Possession is the best example), historical forms of crime and romance novels, fantasy novels inspired by history (even including Lord of the Rings and Game of Thrones), alternate histories and parallel universes (His Dark Materials).

So the definition of historical fiction is changing and deepening, as it has been for some time, and is a broad enough church to encompass books that might also be seen as literary fiction (Wolf Hall, Regeneration, The Luminaries), work that may be set in living memory of the author or members of their family (Atonement, Sarah Waters’ Night Watch), might involve real and imagined characters, and could even, at a pinch, encompass Billy Idol.