The artist set out in 1567 to depict one of the most harrowing stories from the Bible, Herod’s massacre of all infant boys in Bethlehem. But he plainly had another purpose, too. His homeland, Flanders, suffered horribly at the hands of Spanish armies and German mercenaries in the merciless religious wars of his time – from which Britain was saved by the defeat of the Armada. By coupling the hated Spanish with the reviled Herod, Bruegel struck the only blow he could against the invader. But that invader, in the form of Holy Roman Emperor Rudolf II, was soon to come into possession of the painting. Those accused were Rudolf’s allies and relatives. It was too valuable to destroy, so instead he had it altered. The leader of the mounted soldiers– in jet-black armour, centre – originally resembled the Duke of Alva, notorious for his cruelty. His beard has been removed and the features changed. Just in front of him, a heap of dead livestock covers the gruesome pile of murdered children that the painter originally placed there. This is one of many parts of the painting where animals or birds, a swan, a boar, a calf, have been painted over depictions of dead or doomed little boys or male babies. Some have been revealed by infrared imaging (shown in insets) and we have circled others, though there are many more. The red flag carried by the knights has been overpainted to obscure the arms of Jerusalem, a coded reference to the Spanish King, Philip II, who liked to call himself King of Jerusalem. A herald in a red feathered hat, smiling blandly, sits high on a black and white horse, brushing aside the anguished pleas of the villagers. Look closely at the tabard he wears and you can just make out the Habsburg Eagle, beginning to show through the overpainting after 400 years, now that it is safe to tell the truth again.