A 200-year-old painting thought to be a copy has been identified as an original worth thousands - after a piece of paper by the artist was found hidden in the frame

The 'Portrait of a Tyrolese Lady' piece is by renowned 18th century artist Rosalba Carriera.

She is known as the "Queen of Pastel Painting" for painting a series of women from across Italy during the early 1700s and greatly admired by King George III.

The painting was left by Maurice Egerton, the fourth and last Lord Egerton of Tatton, to the National Trust when he died heirless in 1958.

After being placed in storage in the 1980s at Tatton Park in Cheshire it has now been identified as an original piece by a 'stroke of luck'. It was removed from its frame - revealing a slip of paper.

Xavier Salomon, deputy director and chief curator of the Frick Collection in New York, says that the slip of paper was a "Santini".

It features prayers and blessings for a safe passage that the artist hid in works she exported.

Carolyn Latham, the Mansion and Collections Manager, said: "The picture has been in our picture store since the mid 1980s and was thought to be a copy of a Carriera work rather than by her.

"There was a rehang of pictures in one of the state rooms and the work was put into storage.

(Photo: SWNS)

"Xavier Solomon is researching Carriera's works and working on a new catalogue.

''He approached us about visiting to study the work as he believed it could be an actual Carriera.

"Part of this visit and research involved us getting a specialist conservator on site Richard Hawkes to take the work out of its frame and backing to allow an in depth study.

"Xavier had hoped to find the Santini still tucked into the back and we were all really pleased to find it there.

"National Trust collection items are not given a monetary value as they are held in care for the nation."

After extensive restoration, the artwork has now been restored to the collection at Tatton Park and put on display for visitors in the Mansion's Yellow Room until it is closed for winter conservation at the end of October.

A spokesperson for the Tatton Park estate added: "Over time these fragile bits of paper often became lost or separated from her works.

"The discovery of one still in situ at Tatton and confirmation the work was by the artist has been an exciting find for all the team here.

"Rosalba became one of the most popular and sought-after artists. From her beginnings as a painter of scenes for snuff box lids, she moved on to portrait miniatures and then became integral in popularising the use of pastels.

"She was an initiator of the Rococo style and is remembered as one of the most successful women artists of any era, but sometimes her work was considered risqué due to the delicate lace coverings, depicted on the subject's clothing only just saving their modesty."