In Blocula, Sweden, in 1669, according to records there flourished "a great army of witches." The trials that followed were amongst the most terrible events of the Witch Hunts resulting from the Spanish Inquisition. Eighty five witches were burnt at the stake, and many more were flogged weekly for a year. One of the alleged offences practiced on a large scale was the transformation of men into horses. This was accomplished by the witch approaching her victim as he lay sleeping, and slipping over his head an enchanted bridle known as a
hag halter. This would transform him instantly into a horse, and the witch would jump upon his back and ride him to her sabath.
There was a small element of risk for the witch - if the newly-formed horse could contrive to remove the halter (restoring him to his human self) and then place it over the witch's head, the tables would be turned.