FOR most of us the Roman buildings of Caerleon and Caerwent are overlaid by those of later years, their distant message muted by the clamour of our modern world.

But Rosemary Aitken, writing as Rosemary Rowe, has the ability to part time's veil. In her world, the modern buildings magically unbuild themselves to be replaced by Roman barracks and Silurian cities complete with shops, taverns and brothels.

Through this created world moves Libertus, the freed slave turned detective who, having been asked to accompany his patron, Marcus Septimus, to the wild and wooded fringes of the Roman Empire, enters a world of racketeering, treason, murder and rebellion.

For the language teacher who turned writer after an industrial accident, there are, though, many parallels between our own and the Roman world. "Everyone thinks they know about the chariot races, but do they also know that the chariot racers were highly paid professionals who formed teams with team colours, and that the rivalry between fans was so great that fighting often broke out?

"The teams were backed by wine importers who might only allow their brand of wine to be promoted at the race. Isn't that pretty much the hooliganism, sponsorship and advertising we associate with sport today?

"People say the gladiatorial fights were totally at odds with our world, but look at the violence on television. It is not true that gladiators always fought to the death. In major centres like Rome they certainly did, but gladiators were expensive assets. In the provinces it was quite common to let them live to fight another day."

Rosemary Rowe is the maiden name of Rosemary Aitken. She writes the Libertus books under the former name, and those set in Cornwall, the county of her birth, under the latter.

A linguist with strong historical leanings, she went to New Zealand as a young woman and embarked upon life as an academic, writing several best-selling textbooks on the English language and communication. Her French is as fluent as her Latin.

Following an accident at work she retired from teaching and began to write short stories, which was when Libertus, the hero of Enemies of the Empire poked his inquisitive detective's nose into her world.

"By this time I had returned to Cornwall and was writing short stories. "One day my publisher telephoned me and asked me if I had anything with a Roman setting.

"Of course, there was no reason why I should have!" she laughs. "Everything grew out of that first short story. At that time I had no idea that the Roman period, along with the medieval, was going to be a popular setting for detective fiction. Had I known there is so much competition I might never have got involved!"

In fact, through his own quick wits, guided by the skilful plotting of his creator, Libertus has elbowed his way to the forefront in the genre, moving through the shady parts of Silurian Caerwent as if a native.

Rosemary Aitken lives not far over the border in Gloucestershire, and ran several detailed reconnaissance missions into Gwent before settling down to write Enemies of the Empire, which is the seventh in the Libertus series. The eighth book in the series is being written. It has no title as yet, but a kidnapping will be central to the plot.

Detective books set in antique periods are popular, so there is lots of sleuthing for Libertus to do. The Romans, after all, were known for their industry, energy, commercial acumen and - with an empire that outlasted the British Empire by far - their staying power.

'When in Rome, do as the Romans do' might therefore serve as Rosemary Rowe/ Aitken's watchword.

Enemies of the Empire, by Rosemary Rowe, is published by Headline at £18.99.