CNN  — 

A painting of the Last Supper which hung for more than a century in a small English church was created in Titian’s workshop, art historians have found.

The huge painting, which measures more than 12 feet by 5 feet, had garnered little attention on the walls of St Michael and All Angels Church in Ledbury – a market town with about 10,000 residents in western England.

But when art historian and conservator Ronald Moore was called in to work on another piece of art at the Herefordshire church, he became intrigued by the discolored and neglected canvas which had been housed there since 1909.

Then, around three years ago, the church commissioned Moore to research and restore the piece. He told CNN that he and his researcher Patricia Kenny spent some 11,000 hours researching the picture’s history, as well as around three months conserving it.

Their tireless work revealed the untitled artwork, a depiction of the Last Supper, was produced in the workshop of Tiziano Vecellio, more famously known as Italian Renaissance master Titian.

After removing centuries of discolored varnish, they made some incredible discoveries. As well as finding an all-important signature, they identified some of the faces as portraits.

The signature was discovered on the jug.

Moore said: “It wasn’t until I got into the studio and began to examine it that I realized quite how important it was.”

According to Moore, the painting took around 20 years to complete in Titian’s Venice workshop between 1560 and 1580. When Titian died in 1576, he left behind many unfinished pieces which – like this – might have been completed in his workshop.

“It is almost certainly the only large-scale Titian workshop painting that is undiscovered until now. Being created over 20 years, it gives us the opportunity to examine the different hands involved in the workshop.”

The workshop, says Moore, was a “close knit group of painters who could work in Titian’s style.”

He says he can identify at least five “hands” involved in the painting – displaying “different styles and abilities.”

He added: “Titian would surely have created the composition together with probably Francesco, his son.”

Kenny's technique saw her blend the image in the painting with a self-portrait of Titian in order to reveal his identity.

This theory, in part, is supported by the underdrawing that Moore and Kenny discovered. Using ultraviolet light, they also revealed Titian’s signature on a jug in the painting.

Kenny pioneered an innovative technique which revealed “a painting within a painting,” Moore said.

She overlaid images by making them identical in size and opaque, enabling them to identify a portrait of Titian and two of his children. She also removed all “extraneous pigments” to uncover the remains of the signature, added Moore.

The parish church of St Michael & All Saints, Ledbury, Herefordshire, England, where the painting has been hanging for more than a century.

Extensive research revealed that the painting was commissioned by a Venetian convent. Around two centuries later it was bought by an English gentleman called John Skippe. One of the documents the pair uncovered was a letter that Skippe wrote, detailing a Titian painting he had acquired. This led Moore to seek out the signature.

For generations it hung in Upper Hall in Ledbury, before the owners eventually gifted it to the church.

When Moore first took on the job he could not have imagined it would become “the biggest art mystery I have come across.”

The overlay was done with both a sketch and a painting of Titian's portrait.

Moore will not comment on how much the painting might be worth, but said: “It’s not in good condition but it is unique. It’s the first chance we’ve had in art history to be able to look at a Titian workshop painting done over quite a long period of time.”

He believes much of the damage may have been caused by a “careless restoration” after the painting first arrived in England in 1775. Several layers of glaze, together with the damage, would have led to changes and discoloration in the painting.

Ledbury parishioner Ian Beer, who was one of those who commissioned Moore on behalf of the church, told CNN they now have CCTV and will soon be installing special lighting to illuminate the painting without damaging it.

“We are getting more and more visitors from around the world now,” he said. “It has been quite an exciting journey.”

Moore is publishing a book on his findings later this month, called “Titian’s Lost Last Supper.”