There were two versions of this 1890 oil on canvas from the seminal Dutch master, both sowing the good doctor's melancholy expression. This one was originally sold in 1897 by Van Gogh's sister-in-law for 300 Francs. 93 years later and its valued had jumped to a staggering £52,074,000 ($82,500,000) when Christies in New York put it up for auction.