LONDON, ENGLAND.- A small portrait of Mary, Queen of Scots, long considered to date from the eighteenth century, has now been discovered to be an image painted within her lifetime or possibly very shortly after her death. Recent tree ring analysis (known as dendrochronology) has established that the panel, which belongs to the National Portrait Gallery, was felled in the 16th century and the work can now be dated to the period 1560 -1592. Recent conservation work by the Gallery has also revealed an original oval background with a marbling effect, which had previously been over painted with dark brown paint. The portrait, purchased by the Gallery in 1916, is a version of a known type, which also exists in a miniature of around the same date.

The newly conserved portrait - which goes on display at the Gallery tomorrow - may have been painted as an image for one of Mary's supporters either as a symbol of loyalty during her incarceration or as an icon of Catholic martyrdom after death. But why the portrait was overpainted is something of a mystery. There does not seem to be any damage to the surface below and the repaint would have obscured Mary's name, but it is possible it may have been repainted, in the late 18th century or early 19th century, to fit in with a set of other images of European kings and queens.

The portrait depicts Mary following her return to Scotland after her husband, King Francis II of France, died in 1560. This was a period that saw her marriage to Lord Darnley and the birth of her only child, later James I of England/James VI of Scotland. Following Darnley's murder in 1567 and her hasty marriage to the leading suspect, the Earl of Bothwell, Mary was forced to abdicate and escaped to England only to be imprisoned for the remaining 19 years of her life. As the cousin and heir to Elizabeth I, she became the focus for Catholic rebellion and represented a continual threat to the future of Protestant England. After years of plots and intrigue, she was declared guilty of treason and executed on 8 February 1587.

Dr Tarnya Cooper, Curator of 16th Century Paintings, National Portrait Gallery, London, says: "This is an exciting find. The new research on this picture indicates that it was probably painted either in her lifetime or very shortly after her death. This is significant because the vast majority of painted portraits of Mary, Queen of Scots that survive were either painted in the Jacobean period, when her son James I came to the English throne, or are later imaginary portraits. The picture has not been on display for a long time because it was thought to be a much later copy, so it very satisfying to find out that the picture is far more important that we previously thought, and can put it on public display."