This article was provided by Kaye Jones. She has written three titles for the History In An Hour series, and is currently working on another book for Pen & Sword which explores the hidden dangers of the Victorian workplace. See more at her website or follow her Twitter, @kaye_jones.

For my new book, I have traced the life and times of Christiana Edmunds, nicknamed the Chocolate Cream Killer, and one of the most notorious murderesses of the Victorian era. Using records on the Findmypast site, I've been able to discover intimate details about Christiana's life and crimes.

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Christiana's weapon of choice was poison - strychnine and, sometimes, arsenic - and her poisoning spree brought the town of Brighton to its knees over the summer of 1871.Her trial at the Old Bailey in the following year was heavily-attended by the press and public and she was the first woman to have her death sentence respited to a permanent stay in the newly-built Broadmoor Asylum. She lived there until her death from 'senile debility' in 1907. While it was easy to get swept in by the sensational aspects of her crimes, I suspected that there might be more to Christiana's story than passion and passion and, once I got stuck into the research, I was quickly proved right.

Using Findmypast's newspaper archive, I had gleaned a lot of Christiana's biographical details from the press coverage of her trial. I knew, for instance, that she was not a native of Brighton, the scene of her crimes, but was, in fact, born in Margate in 1828. Her father, William Edmunds, was a locally-celebrated architect who married Ann Burn, the daughter of a Royal Marines officer, on New Year's Day in 1828. After their marriage, the couple moved to a large and luxurious house in Hawley Square, one of the most sought-after addresses in town, where they employed three servants.

From the press coverage, I knew that Christiana was the couple's eldest child and she was followed by a son, William, in 1829; two more daughters, Louisa and Mary, in 1831 and 1832; and finally, a son, Arthur, in 1841. The nine-year gap between Mary and Arthur seemed, to me, to be unusually long, considering the health of the couple and the lack of reliable contraception in the period. So, digging further with Parish records, I found two children who died in infancy during this gap: Frederick, in 1833, and Ellen, in 1835. Infant mortality was not uncommon in the Victorian era, even among the wealthier classes, but I couldn't help but wonder if there was a reason why these two babies had died when the other five had prospered.

Using the Findmypast family tree builder, I started to put these details together, all the while wondering about poor Frederick and Ellen. It was only when I returned to researching Christiana's father, William Edmunds, that I made the breakthrough I had hoped for. I knew that William had died in mysterious circumstances in a lunatic asylum in London in 1847 but then, with the help of his death certificate, I learned the cause of his sudden demise: William was suffering from "General Paralysis of the Insane," a Victorian term for the third and final stage of syphilis.

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Whether William knew he had syphilis is subject to some speculation. Syphilis was extremely common in Victorian England, affecting around one-tenth of the population, but its symptoms are not always easy to detect. He may never have noticed, for instance, the small, painless chancre which appears shortly after infection. Even if he did, Victorian doctors were unable to treat it effectively. In fact, the advice to young Victorian men was to go forth and procreate, an idea based on the mistaken assumption that syphilis will eventually go away. But untreated syphilis causes a number of problems for procreating couples, including a high incidence of miscarriage and congenital syphilis, a potentially life-threatening condition for children.

Not all children born to parents with syphilis, however, will develop congenital syphilis. In fact, modern studies suggest that a newly-infected mother has a 59 percent chance of transmitting the infection to her baby but the likelihood decreases for mothers in the later stages of syphilis, to around 13 percent. For those babies who do become infected, they face a number of serious health problems, like fever, gastroenteritis and pneumonia; health issues which can be fatal in young children. Suddenly, the mysterious and sudden deaths of young Frederick and Ellen had a possible explanation.

But what did all this mean for Christiana? Did she have syphilis? Could third-stage syphilis explain the 'madness' she claimed to have at her trial? Initially, I thought it did. It seemed logical to me that her father had contracted syphilis in his days a bachelor, before his marriage to Ann, and that Christiana was, perhaps, suffering from the mental effects of syphilis at the time she committed her crimes. But then I made another discovery which changed my mind once again.

In 1875, Dr Max Kassovitz, a paediatrician and leading figure in the field of congenital syphilis made a remarkable observation on the disease. He proved that congenital syphilis is defined by 'spontaneous gradual diminution in intensity of syphilitic transmission." In other words, with each succeeding pregnancy, the effect of syphilis on a baby will gradually diminish. For the Edmunds family, this means that Frederick and Ellen were the first victims of congenital syphilis and that William became infected with syphilis while married to his wife, not before. According to Kassovitz's law, there is no possibility of Christiana being 'mad' as a result of congenital syphilis.

While syphilis was not responsible for Christiana's actions, it gave me an important insight into her family history. I would never have given much thought to the possibility of syphilis, had I not looked at her family tree and noticed such a large gap between children but, in doing so, I came to view Christiana very differently. Family tragedies, like the deaths of Frederick and Ellen, helped to define the woman that Christiana came to be and we cannot understand the motivations of the so-called Chocolate Cream Killer without them.

Read more about Christiana's story in Kaye's new book, The Case of the Chocolate Cream Killer: The Poisonous Passion of Christiana Edmunds. You can also read more about Kaye's research on her website kayejoneswriter.com and on social media: Facebook.com/kayejoneswriter / Twitter.com/kaye_jones