Perspective is achieved by subtle use of colours

The opening ceremony was attended by Italian government ministers and art critics from many countries.

The nearly unanimous verdict: a meticulous restoration which brings The Legend of the True Cross to life, just like when it was painted 550 years ago.

Restorers used a powerful digital database to get the colour balance right.

Italy's Culture Minister described the work as an extraordinary marriage between old fashioned craftsmanship and new state-of-the-art technology.

Cultural tourism

Piero della Francesca was a precursor of modern European painting.

Italian officials examine the newly-unveiled fresco

He was not a prolific painter, and some of his most important works, originally commissioned for churches in Tuscany, are now in private and public collections in America and Europe.

Piero created the illusion of perspective through a subtle use of colour.

He was also an innovator in the techniques of fresco painting, laying the groundwork for later developments by Michelangelo.

Italy is expecting a big increase in cultural tourism during the coming decade.

The number of both Italian and foreign visitors to archaeological sites, churches, museums and picture galleries grows by millions each year.

The $5m it cost to clean and restore Piero della Francesca's masterpiece was paid primarily by a local bank.

Many business corporations are now sponsoring the arts in Italy.