The only signed and dated image of William Shakespeare created during his lifetime has gone on display in London.
The portrait is being sold by the owner, who wishes to remain anonymous, by private treaty — without an auction — for more than £10 million ($12m).
The image is signed and dated 1608 and is the work of Robert Peake, Sergeant-Painter to King James I.
Before 1975, the portrait hung in the library of a stately mansion in the north of England, once home to the Danby family. Since then it has been in private ownership.
Those behind its sale claim the the connections between Shakespeare and Peake are “extensive”.
The artist was regularly commissioned to paint the portraits of high-ranking members of the Court and Jacobean society.
Those organising the sale say Peake was commissioned by the Office of the Revels, which oversaw the presentation of plays, and worked in a premises in Clerkenwell, London, where some of Shakespeare’s plays were rehearsed.
A 1663 rare first folio of 36 Shakespeare works sold in New York - in pictures
But only two paintings of Shakespeare, both posthumous, are generally recognised as valid.
They are the engraving that appears on the title page of the First Folio, published in 1623, and the sculpture at his funeral monument in Stratford-upon-Avon.
Shakespeare died in 1616 at the age of 52.
Art expert Duncan Phillips, who investigated the work ahead of the sale, said: “There is more evidence for this portrait of Shakespeare than any other known painting of the playwright.
“It is a monogrammed and dated work by a portrait painter of serious status with connections to the artist who produced the image for the First Folio.
“The picture has survived the past 400 years almost untouched by wear and tear thanks to its ownership by a family of Shakespeare enthusiasts who hung it in their library.”
But Shakespeare expert Michael Dobson told the Daily Mail that claims the painting is of the Bard were “wishful thinking”.
The painting went on display on Wednesday at Grosvenor House Hotel, London.