Guilia Tofana (Died 1659) was one of the first women serial killers whose name you probably haven’t heard of. She is known as being a professional Italian poisoner in the 17th century.
Guilia made a concoction, Aqua Tofana named after Guilia, that is thought to be made up of arsenic, lead, and belladonna according to Weird History. In the era of arranged marriages like the Renaissance time, a lot of those marriages led women to be in relationships they did not want to be with men who controlled their every move, body, and even money. Causing very unhappy unions where women had no say in the matter, no way of getting out unless they died, and the men facing no punishment for their actions.
Fueled by this predicament Tofana made it her life goal to help these women in need essentially kill their husbands. She sold cosmetics south of Italy, but one particular one had where three drops of the Aqua Tofana liquid could kill an average man without ever leaving a trace. She was able to remain under the radar for about 50 years, having over 600 victims until a client got cold feet. The client tried to poison her husband, but the husband forced her to confess who sold her the poison and reported Tofana’s name to the police. She was arrested but pled sanctuary to a church that gave it to her, but rumors started that she poisoned the water. So, the police stormed it and she was tortured until she revealed she was responsible.
Guilia Tofana’s name became widely popular where even Mozart on his deathbed claimed to have been poisoned by Aqua Tofana and he felt his death coming.