Portrait of Pastor Swalmius, which has had an uncertain provenance for centuries, has finally been declared a true Rembrandt, after the removal of varnish revealed the artist’s signature. Painted in 1637, the portrait was once owned by the brother of King Louis XIV. In 1886, it was bought by an art dealer and sold to Antwerp's Royal Museum of Fine Arts, where it is on view. "There was a very dark varnish on the painting so subtleties within it were not visible anymore and after time people thought it wasn't genuine," museum spokeswoman Veronique van Passel told the BBC News Web site. After tests showed it was painted on the same linen as two other genuine works by Rembrandt van Rijn, the Rembrandt Research Project confirmed its authenticity.