Friedrich Spee was a German Jesuit priest, professor, and poet, most well known as a forceful opponent of witch trials and one who was an insider writing from the epicenter of the European witch-phobia. Spee argued strongly against the use of torture, and as an eyewitness he gathered a book full of details regarding its cruelty and unreliability. He wrote, "Torture has the power to create witches where none exist."

Kaiserswerth is one of the oldest quarters of the City of Düsseldorf, part of Borough 5. It is in the north of the city and next to the river Rhine. It houses the Kaiserwerth Deaconesses' Institute where Florence Nightingale worked. Kaiserswerth has an area of 4.80 km2 (1.85 sq mi), and 7,923 inhabitants (2020).