London ( CNN ) -- A mystery portrait donated to a British heritage charity as part of a mixed lot of paintings has been identified as a work by Dutch master Rembrandt van Rijn -- worth more than $ 30 million . The picture , dated 1635 , shows the then 29-year-old artist in a black velvet cape and hat decorated with outsized ostrich feathers . It was given to the National Trust in 2010 , along with four other artworks . At the time it was thought to have been painted by one of Rembrandt 's pupils , but new tests and research by leading Rembrandt scholar Ernst van de Wetering have shown it is more likely to be by the teacher himself . `` Over the years , it has gone back and forward , '' David Taylor , the National Trust 's curator of paintings and sculpture , told CNN . `` Decades ago it was thought to be a Rembrandt , and then the experts said no , that it was by someone in his studio instead . '' Van de Wetering , chairman of the Rembrandt Research Project , said the painting was last examined in 1968 , and that in the intervening years `` we have gathered far more knowledge about Rembrandt 's self-portraits and the fluctuations in his style . '' He said that X-ray analysis , along with `` newly found circumstantial evidence remarkably increased the likelihood that the painting was by Rembrandt himself , '' and that a recent close look at the picture had confirmed those suspicions . The painting was given to the Trust by the estate of Edna , Lady Samuel of Wych Cross , whose late husband Harold , Lord Samuel of Wych Cross was a keen art collector and philanthropist . `` It was part of a very generous gift , of five top-notch paintings , '' Taylor explained . As well as the Rembrandt portrait , the donation also included two peasant scenes and two maritime scenes . But while the Trust recognized that the portrait was a high-quality work , it was not put on display at Buckland Abbey , in Devon , southwest England , immediately . `` It was in storage at first , '' explained Taylor . `` Though not because it was unloved , more because we were waiting for the right place for it -- we wanted to get the display right . '' `` It 's amazing to think we might have had an actual Rembrandt hanging here on the walls at Buckland Abbey for the past couple of years , '' Jez McDermott , property manager at Buckland Abbey , said in a statement . `` We never dared think that it might actually be an original , and many of our visitors will have just passed by it , in what is sure to be a real contrast to the attention it is now going to receive . '' The self-portrait , the only Rembrandt in the National Trust 's huge collection of 13,500 paintings , will remain on display at Buckland Abbey until the end of the tourist season -- where it is expected to attract plenty of visitors -- and will then be sent for further tests to help confirm its new identity . `` It will undergo a full clean , and technical analysis , '' said Taylor . `` It is painted on a beech panel , so dendrochronology [ tree ring dating ] will allow us to date the panel , and it will be X-rayed to check for under-drawings . `` The paint will be analyzed , so we can see if the pigments match those used by Rembrandt , and when it comes back to us in the new year , we should have the final confirmation . '' FBI : 1990 art heist cracked .
Painting was donated to the National Trust in 2010 , and put on display at Buckland Abbey . Work was originally identified as being by a follower of Dutch master Rembrandt van Rijn . New tests reveal the portrait , which shows Rembrandt at the age of 29 , is by the artist himself . The painting has been dated back to around 1650 - it's believed that it may have come from his home town Rotterdam or Amsterdam.