#6: The Gospels of Henry the Lion (c. 1175–1188)
Duke Henry the Lion commissioned this Benedictine masterpiece for Brunswick Cathedral. When it appeared at Sotheby’s London in December 1983, bidding lasted three minutes and ended at £8.14 million, roughly $11.7 million, making it at the time the most expensive work of art ever sold at auction. The West German government purchased it back as a national treasure, and it is now held at the Herzog August Bibliothek in Wolfenbüttel.

