Heaven knows, my father did his best. No family holiday was complete without a visit to some windswept ruin, or a site where he paid money to stand in a shed and enthuse over old floor-tiles while the rest of us wandered off in search of somewhere to crack open the Tupperware and the Thermos.

What a disappointment we must have been.

Nevertheless, in the way that family patterns repeat themselves, twenty-five years later I found myself recreating the same scene with our own children at Hadrian’s Wall. Not because I had gained a love of history, but because the Romans are on the National Curriculum.

That day at Housesteads Fort may not have changed our children’s lives, but it changed mine.

I had taken up writing as a hobby some years before, but soon realised that the usual advice to ‘write what you know’ is only of use to people who actually know something. I needed a story, and I didn’t have one.

There’s a fine thriller waiting to be written about Housesteads, where excavators found the skeletons of a man and a woman buried under the floor of a building just outside the gates. My inspiration, however, was less gruesome.

‘Roman soldiers were not allowed to marry,’ declared the caption in the museum, ‘but they were allowed to have relationships with local women.’

It was as if that simple statement had flicked a switch. All sorts of questions arose. What did the local men make of the soldiers ‘having relationships’ with their girls? What happened to the women if the soldiers were moved on? Where did the children go? Suddenly these Ancient stone rectangles full of grass were lived in by real people with hopes and fears and family troubles - and I had the germ of a story.

After all those wasted years, I also had a lot of catching-up to do. Naively pursuing ‘the truth about the Romans’ led me a fine dance around bookshops and libraries and museums and television programmes and re-enactments and finally into the clutches of archaeology – from which, it seems, it is very hard to escape.

My Legionary doctor Ruso and his British woman live, love and unravel murder mysteries in the early years of Hadrian’s reign. There’s almost no British History recorded for this period, and all the surviving texts that cover the centuries of the occupation were written with Roman pens. The Britons are silent. With so little to cling to, I wanted to make the story as archaeologically accurate as possible.

Days spent scraping at a Northamptonshire hillside with a trowel or scrubbing chunks of tile with a toothbrush make serious inroads into the writing time. However, being part of a team on a Roman Villa dig does give a very real sense of both the physical reality and the utter mystery of our ancestors. We can place our own fingertips inside the marks left by theirs in the soft clay of the drying tiles. We can smile at a little graffiti man scratched into a flat surface - perhaps by a bored worker when the foreman wasn’t looking. We know some of them were literate, because we’ve found a writing stylus. But we don’t have the slightest clue who they were.

That particular hillside appears to have held a peaceful sheep farm, but further north and west, Britain was heavily and expensively garrisoned throughout the occupation - suggesting that the local tribes never did succumb to the lures of hot baths and central heating. The contempt may have been mutual. The only description we have of the natives by a serving military unit refers to them as ‘Brittunculi’ – ‘wretched little Brits’. Yet huddled outside most of the forts are buildings that would have served as shops and bars and businesses run by people eager to part the soldiers from their salaries. They would also have provided lodgings for the soldiers’ unofficial families. This meeting-ground of different cultures is the context of the first two books in the Ruso series (known as Medicus in the USA).

The latest book takes a different slant. I wanted to place a Briton in a ‘civilised’ country. In Ruso and the Root of All Evils (Persona non Grata in the USA) our hero takes his British girlfriend home to southern Gaul. What would a woman from a round house and a barter economy make of the splendid temples, the shops and the amphitheatres? Not to mention the heat, the wine, the ex-wife and the in-laws?

It was entertaining to speculate. In truth we know very little of what the Britons thought of Rome, although Cassius Dio records a smart put-down from a Caledonian woman to an Empress who had commented on the morals of her countryfolk:

‘We fulfil the demands of nature in a much better way than you Roman women; for we consort openly with the best men, whereas you let yourselves be debauched in secret by the vilest.’

Ouch.

Little snippets like that provide teasing glimpses of lost conversations, suggesting the peoples of the Ancient world were ‘just like us’. Some of the letters that have miraculously survived at the fort of Vindolanda give the same impression: there’s a famous birthday party invitation and a note about the supply of socks and underpants. Yet in other ways our ancestors’ thinking must have been very alien to our own. How do you get into the mind of a society where a public holiday could be celebrated by having hundreds of people and animals killed in the most spectacular ways possible? Where nobody questions the buying and selling of human beings as property? Where a man can send home a letter to his pregnant wife saying that she is only to bother rearing the baby if it’s a boy?

The tensions between the native and the occupier, the familiar and the alien, the known and the tantalisingly unknowable, are what fascinate me about the Roman Empire.

It might be true that history becomes more interesting the nearer I get to becoming part of it, but it’s also true that its presentation has changed over the years. These days it’s hard to find unexplained displays of Roman floor-tiles in sheds (although there’s still a marvellous one in the Cotswolds). Twenty-first century children are introduced to their heritage in ways that are engaging and approachable. But for any parents who still despair of their offspring showing any interest – take heart. In years to come they may, like me, suddenly realise what they’ve been missing.

Ruso and the Root of All Evils by R S Downie is published by Penguin on 29th April 2010 and is available from HistoryDirect.co.uk