1453: Roger de Arras fights in the battle of Castillon. The same year he publishes his Poem of the Rose and the Knight in Nuremberg. (A copy can be found in the Bibliotheque National in Paris.)

1455: Van Huys paints Virgin of the Chapel. (Undated, but experts place it at around this period.)

1457: Wilhelmus Altenhoffen, Duke of Ostenburg, dies. He is succeeded by his son Ferdinand, who has just turned twenty-two. One of his first acts would have been to call Roger de Arras to his side. The latter is probably still at the court of France, bound to King Charles VII by an oath of fealty.

1457: Van Huys paints The Money Changer of Louvain.

1458: Van Huys paints Portrait of the Merchant Matteo Conzini and His Wife.

1461: Death of Charles VII of France.

Presumably freed from his oath to the French monarch, Roger de Arras returns to Ostenburg. Around the same time, Pieter Van Huys finishes the Antwerp retable and settles in the Ostenburg court.

1462: Van Huys paints The Knight and the Devil. Photographs of the original (in the Rijksmuseum, Amsterdam) suggest that the knight who posed for this portrait could have been Roger de Arras, although the resemblance between the character in this painting and that in The Game of Chess is not particularly marked.

1463: Official engagement of Ferdinand of Ostenburg to Beatrice of Burgundy. Amongst the embassy sent to the Burgundy court are Roger de Arras and Pieter Van Huys, the latter sent to paint Beatrice’s portrait, which he does this year. (The portrait, mentioned in the chronicle of the nuptials and in an inventory of 1474, has not survived.)

1464: The Duke’s wedding. Roger de Arras leads the party bringing the bride from Burgundy to Ostenburg.

1467: Philip the Good dies and his son, Charles the Bold, Beatrice’s cousin, takes over the duchy of Burgundy. French and Burgundian pressure intensifies the intrigues within the Ostenburg court. Ferdinand Altenhoffen tries to keep a difficult balance. The pro-French party back Roger de Arras, who has great influence over Duke Ferdinand. The Burgundian party relies on the influence of Duchess Beatrice.

1469: Roger de Arras is murdered. Unofficially, the blame is laid at the door of the Burgundy faction. Other rumours allude to an affair between Roger de Arras and Beatrice of Burgundy. There is no proof that Ferdinand of Ostenburg was involved.

1471: Two years after the murder of Roger de Arras, Van Huys paints The Game of Chess. It is not known whether the painter was still living in Ostenburg at this time.

1474: Ferdinand Altenhoffen dies without issue. Louis XI of France tries to exercise his dynasty’s former rights over the duchy. This only worsens the already tense relations between France and Burgundy. Charles the Bold invades the duchy, defeating the French at the battle of Looven. Burgundy annexes Ostenburg.

1477: Charles the Bold dies at the battle of Nancy. Maximilian I of Austria makes off with the Burgundian inheritance, which will pass to his nephew Charles (the future Emperor Charles V) and ultimately belong to the Spanish Habsburg monarchy.

1481: Pieter Van Huys dies in Ghent, whilst working on a triptych intended for the cathedral of St Bavon, depicting the Descent from the Cross.

1485: Beatrice of Ostenburg dies in a convent in Lieges.

For a long while, no one dared speak. They looked from one to the other and then at the painting. After a silence that seemed to last forever, Cesar shook his head and said in a low voice, “I must confess I’m impressed.”

“We all are,” added Menchu.

Julia put the documents down on the table and leaned on it.

“Van Huys obviously knew Roger de Arras well,” she said, pointing to the papers. “Perhaps they were friends.”

“And by painting that picture, he was settling a score with the murderer,” said Cesar. “All the pieces fit.”

Julia walked over to her library, consisting of two walls covered with wooden shelves buckling beneath the weight of untidy rows of books. She stood there for a moment, hands on hips, before selecting a fat illustrated tome, which she leafed through rapidly. Then she sat down between Menchu and Cesar with the book, The Rijksmuseum of Amsterdam, open on her knees. It wasn’t a very large reproduction, but a knight could clearly be seen, armour-clad, head bare, riding along the foot of a hill on top of which stood a walled city. Next to the knight, engaged in friendly conversation, rode the Devil, mounted on a scrawny black horse, pointing with his right hand at the city towards which they seemed to be travelling.

“It could be him,” said Menchu, comparing the features of the knight in the book with those of the chess player in the painting.

“And it could just as easily not be,” said Cesar. “Although, of course, there is a certain resemblance.” He turned to Julia. “What’s the date of this painting?”

“ 1462.”

“That’s nine years before The Game of Chess was painted. That could explain it. The horseman accompanied by the Devil is much younger.”

Julia said nothing. She was studying the reproduction.

“What’s wrong?” Cesar asked.

Julia shook her head slowly, as if afraid that any sudden move would frighten away elusive spirits that might prove difficult to summon up again.

“Yes,” she said, in the tone of one who has no alternative but to acknowledge the obvious. “It’s too much of a coincidence.” And she pointed at the page.

“I can’t see anything unusual,” said Menchu.

“No?” Julia was smiling. “Look at the knight’s shield. In the Middle Ages, every nobleman decorated his shield with his particular emblem. Tell me what you think, Cesar. What’s painted on that shield?”

Cesar sighed as he drew a hand across his forehead. He was as amazed as Julia.

“Squares,” he said unhesitatingly. “Black and white squares.” He looked up at the Flemish painting, and his voice seemed to tremble. “Like those on a chessboard.”

Leaving the book open on the sofa, Julia stood up.

“It’s no coincidence,” she said, picking up a powerful magnifying glass before going over to the painting. “If the knight Van Huys painted in 1462 accompanied by the Devil is Roger de Arras, that means that, nine years later, the artist chose the theme of his coat of arms as the main clue in a painting in which, supposedly, he represented his death, given the floor of the room in which he placed his subjects is chequered in black and white. That, as well as the symbolic nature of the painting, confirms that the chess player in the centre is Roger de Arras. And the whole plot does, indeed, revolve around chess.”

She knelt down in front of the painting and peered through the magnifying glass at the chess pieces on the board and on the table. She also looked carefully at the round convex mirror on the wall in the upper left-hand corner of the painting, which reflected the board and the foreshortened figures of both players, distorted by perspective.

“Cesar.”

“Yes, love.”

“How many pieces are there in a game of chess?”

“Urn… two times eight, so that’s sixteen of each colour, which, if I’m not mistaken, makes thirty-two.”

Julia counted with one finger.

“The thirty-two pieces are all there. You can see them really clearly: pawns, kings, queens and knights… Some on the board, others on the table.”

“Those will be the pieces that have already been taken.” Cesar had knelt down by her and was pointing to one of the pieces not on the board, the one Ferdinand of Ostenburg was holding between his fingers. “One knight’s been taken; only one. A white knight. The other three, one white and two black, are still in the game. So the Quis necavit equitem must refer to that one.”

“But who took it?”

Cesar frowned.

“That, my dear, is the crux of the matter,” he said, smiling exactly as he used to when she was a little girl sitting on his knee. “We’ve already found out a lot of things: who plucked the chicken and who cooked it. But we still don’t know who the villain was who ate it.”