Experts are trying to establish if a 15th century painting of a pretty blonde with piercing blue eyes could be the first picture of France's national heroine Joan of Arc, Culture Ministry officials said on Tuesday.

The wall painting was discovered a year ago in a chapel at Joan of Arc's birthplace in Domremy, eastern France, where historians say she used to pray. If it is authenticated it will be the only painting of Joan when she was alive.The painting shows a teenage girl with blue eyes, full cheeks, blond hair and peasant headgear kneeling besides a saint, Thiebaut de Provins.

The local bishop was reported to have said in church last week that the picture, discovered by workers under a layer of lime spread on the walls during a 16th century plague epidemic, was that of Joan of Arc.

A Culture Ministry spokeswoman said this had not been confirmed and that its experts were studying the painting.

The painting was dated at the start of the 15th century, which makes it the only known picture of France's patron saint made during her life. Countless paintings have been done since her death.

Joan of Arc is best known for leading a campaign to eject the English from France. She was burned at the stake in 1431 at age 19.