“It may sound ridiculous, but please do not dig any holes on the Kalandeberg”, the Mayor of Ghent instructed its citizens on Friday (15 June) after it emerged that a missing masterpiece may be buried under the cobbled square in the city centre.

The theft of the untraced panel from Hubert and Jan van Eyck’s ‘Adoration of the Lamb’ altarpiece is considered one of the greatest art robberies of all time. It was one of two panels from the Ghent altarpiece stolen from St Bavo’s Cathedral on the night of 10 April 1934. The panel depicting St John the Baptist was rescued after the Belgian government received a ransom demand for 1 million Belgian francs and negotiated for its return. Last week, industrial engineer and amateur puzzler, Gino Marchal, shared his theory as to the whereabouts of the final missing panel depicting the ‘just judges’.

According to Marchal, the key to unlocking the mystery lay in a ransom letter retrieved from the desk drawer of a stockbroker named Arsène Goedertier. On his deathbed, Goedertier confessed to his lawyer that he knew the whereabouts of the “Mystic Lamb” and directed him to an envelope stored in his writing table. It contained carbon copies of thirteen ransom notes sent as part of the negotiation for the St John the Baptist panel together with an unsent fourteenth letter containing the following clue:

“[It] rests in a place where neither I, nor anybody else, can take it away without arousing the attention of the public”.

It is Marchal’s view that five words and one number in the fourteenth later plot a route to the location of the missing panel buried beneath the Kalandeberg. In September 2017, he contacted Belgian police to inform them he had cracked the code. The Mayor of Ghent advised that the public prosecutor’s office “takes this theory very seriously” and detectives are now investigating the possibility of digging under the city square.

‘Adoration of the Lamb’ is considered one of the most influential artworks in history and potentially the world’s first great oil painting. Seized by the Germans during the First World War, it was returned under the Versailles Treaty, looted by the Nazis in 1942 and returned once again to Ghent with the assistance of the ‘Monuments Men’.