Up until 1788, portraits of Charlotte often depict her in maternal poses with her children, and she looks young and contented; however, in that year her husband fell seriously ill and became temporarily insane. It is now thought that the King was suffering from porphyria, but at the time the cause of the King's illness was unknown. Sir Thomas Lawrence's portrait of her at this time marks a transition point, after which she looks much older in her portraits; the Assistant Keeper of Charlotte's Wardrobe, Charlotte Papendiek, wrote that the Queen was "much changed, her hair quite grey".