The early church did not execute witches, seeing them as reformable, but in the Middle Ages the campaign against heresy intensified. Reliance on secular power to kill diabolists was considerable. Traditionally, European justice was dispensed locally, with the onus on individuals to prove their case. Ordeals were key. After 1215 Roman law inquisitions assumed responsibility for determining truth — though in practice, law officers relied upon information from ordinary witnesses. The stories of Reformation and witch-hunt are elaborately intertwined, but ‘Justice’ argues that there was no coherent, coordinated pan-European campaign. We now know that witch-trials were rarer than was once supposed, with around half those tried being executed.