Ritratto di George Villiers, I duca di Buckingham

George Villiers, Duke of Buckingham, was the most powerful courtier in England, the favourite first of King James and then of Charles the First, envied and resented in equal measure. Rubens met him in Paris in 1625 and worked up this oil sketch of his head, a study for a grander portrait that has since been lost. Three years later Buckingham was stabbed to death by a discontented army officer, so finished likenesses of him are few. For a long time this sketch sat in storage in a Glasgow house, catalogued as a mere copy. Only in 2017, after an art historian took a closer look and layers of old varnish and overpaint were removed, was it recognised as Rubens's own work and moved to the Kelvingrove gallery.