A painting hanging in the former home of Sir Francis Drake has been confirmed as a self-portrait by the Dutch Master Rembrandt, the National Trust has announced.
For decades the picture, which has been at Buckland Abbey in Devon since it was given to the trust in 2010, was thought to have been a portrait produced by one of Rembrandt's pupils.
But years of studying the 17th-century artist's style and a new investigation of the painting by the world's leading Rembrandt expert, Ernst van de Wetering, has re-attributed the painting as a work by the Dutch Master himself.
The painting, kept in storage for the first 18 months it was at Buckland Abbey as there was nowhere to hang it, is now one of the National Trust's most important.
It has been given a value of £20 million, although as the trust holds items on behalf of the nation forever, the organisation said it can never be sold.
The painting was given to the National Trust as a gift from the estate of the late Edna, Lady Samuel of Wych Cross, whose husband Harold, Lord Samuel of Wych Cross, collected a great number of paintings during his lifetime.
The self-portrait showing Rembrandt aged 29, "signed" by the Dutch Master and dated 1635, previously belonged to the Princes of Liechtenstein.
Its provenance had been shrouded in mystery for 40 years, after Rembrandt specialist Horst Gerson suggested in 1968 that it may well have been painted by one of Rembrandt's pupils. In the same year members of the Rembrandt Research Project inspected the painting and came to the same conclusion, publishing their findings in 1989.
Mr van de Wetering, Dutch art historian and chairman of the Rembrandt Research Project, said that based on what was known of the painter's style in 1968, experts decided it was most likely to have been painted by one of his pupils.
"But over the past 45 years we have gathered far more knowledge about Rembrandt's self-portraits and the fluctuations in his style," he said.