But it’s not only ferocity that makes a battle famous. In 1503, after exiling Piero the Fatuous and the rest of the Medici, and after Savonarola met his fiery fate, the Florentines celebrated the return of their Republic by commissioning, from Leonardo da Vinci, a vast mural of the Battle of Anghiari for one wall of the Palazzo Vecchio’s Council Hall. (For the opposite wall, they commissioned another battle scene, from Michelangelo.)Michelangelo completed his preparatory drawings quickly. But before he could begin painting, he was called away to Rome by Pope Julius II.

Leonardo made his preparations, and began to paint. But Leonardo hated fresco, so perhaps he used oils, or an encaustic (coloured wax) method he read of in Livy. Unfortunately, the colours would not dry properly. He built a fire to dry the upper part of the image, but humidity from a sudden rainstorm caused the lower part to run. Leonardo gave up.

The abandoned painting remained on the wall, deteriorating. Leonardo’s fame ensured that artists flocked to view and copy it. Rubens made a famous copy of a copy, depicting a fierce collision of snarling horsemen. But in 1563, Duke Cosimo I ordered Giorgio Vasari to cover the walls with frescoes of his own. Giorgio was not a man to leave a job undone – Leonardo’s Battle of Anghiari was seen no more.In Vasari’s painting, among a crowd of soldiers, a pennant flies, bearing the words Cerca, Trova – Seek and Find.

Did Vasari preserve Leonardo’s picture behind a fake wall, and leave a cryptic clue for us? Perhaps. In 2012, holes were drilled in Vasari’s fresco. An airspace was found behind it. A little paint residue was retrieved. But art historians and conservators objected strenuously to damaging Vasari’s work, and for now the investigation has stopped.