On 18 March 1612 Alizon Device was out begging near Colne in Lancashire, when she met a pedlar called John Law. The pedlar refused the young woman's request that he should show her his wares, and when Alizon grew angry with him, a black dog appeared and offered to harm the pedlar on her behalf. When Alizon said 'lame him', the dog promptly did so. The left side of Law's body was paralysed, and, as a result, Alizon Device was tried and subsequently executed for witchcraft at the Lancaster assizes a few months later.

How do we know about this incident? The answer is that Thomas Potts, the clerk of the court before which Device and nine others appeared, wrote and published a lengthy account of the trials, based heavily on the documentation created by the legal process. It is on an analysis of