On the 25th November 1934, Arsene Goedertier, a Flemish stockbroker, lay dying in the city of Ghent. As he wheezed his last gasps, the man’s solicitor leaned in to hear his client’s final words. To the lawyer’s surprise, the stockbroker didn’t express some expected reflection on the transience of life, nor did he stipulate further provisions for his heirs. Instead, he confessed to being the mastermind behind one of the most famous art heists in history.

The Just Judges, a panel from van Eyck’s The Adoration of the Mystic Lamb, had vanished seven months before, along with another piece of the priceless polyptych, a section showing Saint John the Baptist. The stockbroker reportedly whispered into his attorney’s ear “I alone know where the Mystic Lamb is”, ending persistent speculation about the identity of the thief in the eyes of some observers. Twelve ransom notes had been sent to the diocese of Ghent and in Goedertier’s desk, the drafts of those letters, with lines for a thirteenth unsent message, were found. The thief returned the panel of John the Baptist as an “act of goodwill” while negotiating the return of the Just Judges with the Belgium authorities. But, to this day, the location and condition of the finishing piece to van Eyck’s astonishing allegorical puzzle remains a mystery.