Peter Niers, notorious German bandit (date of birth unknown)
Peter Nigers (or Niersch) (c. 1540 – 16 September 1581) was a German serial killer and bandit who was executed on 16 September 1581 in Neumarkt in der Oberpfalz, some 40 km from Nuremberg. Based on confessions extracted from him and his accomplices under torture, he was convicted of 544 murders, including 24 fetuses cut out of pregnant women—allegedly, the fetal remains were to be used in magical rituals (he was believed to be an extremely powerful black magician, with many supernatural abilities) and for acts of cannibalism.
Information about Niers is based on contemporary ballads, "true crime" reports, and official warrants circulating, as well as the aforementioned confessions extracted under torture.
It is unknown whether he actually did kill 544 people, or whether this was just a confession under torture.