How did the Gallery discover that this was a work by the Renaissance master Raphael? The answer lies partly in the art historical expertise of scholars and curators both inside and, just as importantly, outside the National Gallery.
Since The Madonna of the Pinks was first examined by Dr Nicholas Penny - and the findings published in the Burlington Magazine - leading experts from all over Europe and America have examined the painting and concluded that it is by Raphael.
Their view is based on their knowledge of Raphael's painting style and technique, as well as the provenance of the picture and detailed scientific examination.
The only possible conclusion from this evidence is that the picture is entirely characteristic of Raphael. It cannot plausibly be attributed to anybody else of his time, and cannot have been painted at a later date.