The Telegraph tells the story of a John Constable drawing that remained hidden for a century and a half because the aristocrat who owned it was shy. The album of constable’s work had a dinner invitation pasted over it:

The owner did not tell anyone about the sketch and its existence remained unknown until 145 years later when an art enthusiast purchased the album. The art dealer peeled off the invitation to expose the Constable original, which is thought to have been drawn in 1808. Although there was some minor glue staining on it, covering it for so long actually helped preserve the condition of the drawing. Constable was famed for his landscape paintings, including the Hay Wain, but he was also an accomplished portrait artist and occasionally drew nude figures. The sketch had an estimate of about £5,000 when it came up for sale at auction at Bonhams of London but sold for four times that amount.

Naked Sketch by Constable Comes to Light after 145 Years (Telegraph)