Although the main focus is Lizzie – who was accused but later acquitted of murdering her father Andrew and stepmother Abby with a hatchet in 1892 – the show explores the legacy of female rage.

As such, Monster jumps forward in time to examine serial killer Aileen Wuornos, who is inspired by Lizzie in this version of events (despite there being no historical evidence to suggest this was true).

But it also goes further back thanks to Bridget “Maggie” Sullivan introducing Lizzie to the story of Báthory, a Hungarian noblewoman who has gone down in history as one of the most prolific female serial killers ever. Vicky Krieps plays both Maggie and Báthory, with the latter appearing in graphic flashbacks.

According to legend, Báthory tortured and murdered hundreds of girls and young women between the late 1500s and early 1600s, with her victim count sometimes placed at a staggering 650.

She’s also famously said to have bathed in the blood of virgins to preserve her youth, something Monster very much leans into. Lizzie even recreates the blood bath herself using cherry juice.

But just like the supposed connection between Lizzie and Báthory, a lot of what we think we know about the Blood Countess is far from historical fact. And that includes the story that Báthory recorded 650 victims in her own private diary.

Did Elizabeth Báthory really confess to killing 650 people in a diary?

You might be relieved to know there’s no diary in existence featuring a confession from Elizabeth Báthory that she murdered 650 people. The number does have a source, but it’s definitely not a reliable one.

According to the Guinness World Records, Báthory and four of her servants were arrested and interrogated after an investigation into the alleged killings. During the proceedings, one servant claimed a court official, Jakab Szilvássy, had seen the number 650 written in one of Báthory’s private books.

Not only did Báthory herself never confess to killing 650 women, but Szilvássy never mentioned the book in his own testimony. And even though rumours of a secret journal have circulated for centuries, the National Archives of Hungary – which holds official documents from the case – doesn’t have one.

Báthory.org includes an email from National Archives of Hungary archivist Gera Zsófia, who explained that they preserve several documents such as Báthory’s personal letters and legal files.

But when it came to the diary, Gera said, “Unfortunately, we know nothing about the location of the diary.” She added that it was once believed to be held by a private collector in Nagyszombat – now Trnava in Slovakia – “but later turned out that it was a gossip”.

So how much of the Blood Countess story has actually been confirmed?

In short, not a lot. According to the Hungarian National Archives, 317 witnesses were questioned during the investigation into Báthory between 1610 and 1611. But most of them only knew about the alleged crimes through hearsay.

The Archives website says that investigators couldn’t find a witness who could credibly prove Báthory herself had committed the crimes she was accused of, and no relatives of the supposed victims came forward either.

When officials and soldiers arrived at Čachtice Castle in 1610, they also reportedly found no evidence proving she had murdered hundreds of girls.

Some of the most damning evidence was witness testimony from Báthory’s servants, but there’s a problem with that too: they were tortured.

As said by the Guinness World Records, “Elizabeth’s servants did not confess to their alleged crimes until they were subjected to extreme torture methods, such as having their fingers torn out with red-hot pincers.” It goes without saying that none of that would pass today.

Nonetheless, everyone involved was punished… and not lightly. Three servants were burned alive – including one who initially escaped and was later caught – another was beheaded, and one was given a life sentence.

As for Báthory herself, she was spared execution and sentenced to house arrest. She was confined to her castle for the rest of her life, eventually dying in 1614 at the age of 54.

To this day, we still can’t know the full truth, but what we do know is that the evidence was shaky at best, and it’s something historians still debate. There are allegations of servants being abused and deaths happening at her estate, while some historians believe she could have been the subject of a witch hunt.

But it does mean the image of Báthory as a vampiric serial killer who confessed to 650 murders is nowhere near as historically certain as the legend – or Monster – makes it seem.