It has been one of the more intriguing art historical mysteries for more than a century: did the great pre-Raphaelite Dante Gabriel Rossetti touch up a Botticelli painting he owned by giving the sitter a vibrant red rinse?

On Thursday, curators at the Victoria and Albert Museum gave the definitive answer – the red hair of the 15th-century woman known as Smerelda Bandinelli is her own and the supposed Rossetti intervention can finally be laid to rest as a myth.