Today very little is visible of what was, for five centuries, one of the main monuments of imperial Roman power. The theatre complex is buried beneath layer upon layer of history. New excavation work is impossible

But far away, in a small office at the University of Warwick, Pompey's theatre is being recreated - on a computer screen. "We are constructing a 3D jigsaw of the site", says Professor Richard Beacham, head of a team engaged in what's known as the Pompey project. "It's virtual archaeology. We can rebuild the theatre and take you inside, on to the stage or hundreds of feet away to the back where the slaves sat. Then you can really feel what it was like to watch a performance in those days.

the Pompey project is part of a wider scheme to apply multimedia technology to the world of theatre. Armed with a £450,000 grant from the EU, Beacham and his team at the department of Theatre Studies at Warwick are recreating 30 theatre site in Europe, ranging from the Odeum of Pericles in Athens to the Globe theatre in London.

"Take us to Agrippa", says the professor to one of this assistants. A click of the mouse and a 3D image of the Odeum of Agrippa, built in Athens in 12BC, appears. Another click, and we are inside, taking seats in the third row on the left, looking at the actors, noting the shadows cast on the stage. Says Beacham: "Now technology has caught up with imagination. The computer allows you to actually experience sitting there in the Pompey theatre, with the actor a tiny speck on the stage, 300ft away. And by learning about the setting of a play you can understand aspects of the drama much better.

Before designs are committed to computer, all known texts and illustrations are collated. Photographs and measurements are taken of the site. the Warwick team spent hours searching out and measuring columns in the cellars of Rome as part of the research into the Pompey project. A firm of specialist architects in Berlin evaluates all aspects of the plans. The imagery, along with explanations, footnotes and other data, is put on the world wide web.

Creating virtual theatres has other advantages. Students find accessing models on the screen more interesting than reading books or listening to lectures. "I can tell my students to go and look at the web and take a stroll through the Globe", says Beacham. "inside, they can search out various other pieces of information - on costume, set design or details of the plays stages there ... it's far more engaging than a lecture or set of slides."

The Warwick team says it is the leader in it's field. Theatron, a limited company, has been set up to exploit commercial opportunities associated with the teams work. Beacham foresees a time when visitors to Europe's ancient theatre sites will be able to access a virtual model on a nearby computer screen. Electronic exhibitions of theatre history and design can be created and constantly added to at a fraction of the cost of building replicas out of boards and bolts.

Other virtual effects are in the pipeline: the department of engineering at the University of Ferrara in Italy is working on replicating the sounds of ancient theatre -recreating the actors' voices, the chatter of the audience and the acoustics of hundreds of years ago.

Martin Blazeby, a multimedia designer with the Warwick team, argues: "Theatre itself is built on illusion. Through virtual reality we are taking things one step further and creating an illusion of an illusion.