The Lancashire Witches is a historical novel is based on the true story of the Pendle witches, who were executed in 1612 for causing harm by witchcraft. Ainsworth based his story largely on the official account of the Lancashire witch trials written by the clerk to the court, Thomas Potts, first published in 1613 under the title The Wonderfull Discoverie of Witches in the Countie of Lancaster. The trials took place not quite seven years after the Gunpowder Plot to blow up the Houses of Parliament in an attempt to kill King James and the Protestant aristocracy. It was alleged that the Pendle witches had hatched their own gunpowder plot to blow up Lancaster Castle, although historian Stephen Pumfrey has suggested that the 'preposterous scheme' was invented by the examining magistrates.