For all its charm, no one could describe the medieval town of Cortona in Tuscany as a happening kind of place. Perched on a hilltop, a hour’s drive from Florence, its “attractions” number three monasteries, two convents and one preserved corpse of a thirteenth century saint, Margherita, which lies in a glass coffin inside the main church.

Tourists tend to congregate around a small central piazza, offering a Spar supermarket and handful of antique shops. Yet in August, this unprepossessing corner of Italy is expected to attract 10,000 visitors for the Tuscan Sun Festival - an event that organisers hope will put Cortona on the map as one of the premier destinations for classical music in Europe.

For two weeks, the town will play host to the sort of internationally-renowned musicians who could keep the Royal Festival Hall in ticket sales for months. Opening the festival is Sophia Loren, whose conductor son, Carlo Ponti Jnr, is directing the Russian National Orchestra in a recital of his film producer father’s most famous scores.

Jose Cura will be performing an open air concert outside the Sancturio St Margherita, while a chapel next to the Franciscan monastery will see a low-key appearance by Anna Netrebko, the Russian soprano who, myth has it, was discovered mopping floors in a theatre in St Petersburg. Says Barrett Wissman, the Texan impresario who is staging the event, “I can think of few other classical music festivals that have such a high level of artists in such a concentrated way.”

Cortona is, naturally, not the only Italian town that is putting on a few concerts this summer. July and August is traditionally opera season in Tuscany, and there is hardly a square within a 100-mile radius that isn’t temporarily turning itself an alfresco amphitheatre for performances of Puccini or Verdi. In just five years, though, Cortona has pulled off the feat of becoming as renowned for classical music as Bunel in Spain is for tomato-throwing.

The reason? “The town has a very special feel to it,” says Wissman. “We may not be have the biggest or most impressive line-up, but there is an intangible magic to the festival that you can’t quite put your finger on.”

“Magic” aside, its strength is also due to considerable musical muscle. Wissman is owner of IMG Artists, the management agency for classical performers, while his wife is Nina Kotova, the cellist. The couple have been holidaying in Tuscany since 1995, and initially devised the festival as a one-off event for their friends. Wissman says that at first, he simply wanted to get people inside Cortona’s Fellini-on-mothballs theatre, Teatro Signorelli. “It was incredible to me that this beautiful place was hardly being used. If it was in London or Vienna, people would be all over it.”

Wissman maintains the festival’s informal vibe has remained, despite its growing international audience. The Russian baritone Dmitri Hvorostovsky has praised the “bohemian” atmosphere, a word that may surprise non-classical music fans. “The concerts all feel relaxed and intimate, with no more than a few hundred people in the audience,” says Wissman. “There are parties in the evening. People dress casually. It all makes for an electric atmosphere.”

It’s not exactly Glastonbury - you are still unlikely to see anyone on day-glo stilts, or rolling around in mud - but it is the sort of event where you can stumble, wine glass in hand, from dinner to open air concert to late night recital. In fact, you’re encouraged to. In addition to the classical concerts, there are plenty of extra curricular activities, including wine tastings, cookery demonstrations, a retrospective of Carlo Ponti’s films in a derelict medieval church and “wellness” seminars on everything from yoga to Chinese medicine.

Wissman hopes that the diverse mix will attract not just classical music fans, but also the British, French and German tourists who already holiday Tuscany. So is everyone a winner? Well, not quite. “People in Italy are a little conservative,” says Wissman, explaining the locals’ reticence to make the most of cheap tickets. “They don’t like change. But this festival is bringing business to the town, and a fresh image. People are becoming more accepting of what we’re doing.”

For visitors, at any rate, the festival offers a chance to catch the biggest names in classical music in a setting that feels like nothing less than a 3D Renaissance painting. “We have some of the greatest artists in the world performing in a place that lives and breathes history,” says Wissman. Many people would go much further for much less.

NEED TO KNOW

Times recommends

• Oasis of the Seas: the Times review
• The 20 best new year party places to stay
• Green Spaces 2009: are you the winning writer?