(excerpt from Wikipedia)
Countess Elizabeth Báthory (Báthory Erzsébet in Hungarian, Alžbeta Bátoriová in Slovak, Alžb?ta Báthoryová in Czech, El?bieta Batory in Polish, 7 August 1560 – 21 August 1614), was a Hungarian countess from the renowned Báthory family. She is possibly the most prolific female serial killer in history and is remembered as the “Blood Countess” and as the “Bloody Lady of ?achtice”, after the castle near Trencsén (Tren?ín), in the Kingdom of Hungary, where she spent most of her adult life.
The Báthory family defended Hungary against the Ottoman Turks.
After her husband’s death, she and four collaborators were accused of torturing and killing hundreds of girls and young women, with one witness attributing to them over 600 victims, though she was only convicted on 80 counts. In 1610, she was imprisoned in ?achtice Castle, where she remained bricked in a set of rooms until her death four years later. She was never formally tried in court.
The case has led to legendary accounts of the Countess bathing in the blood of virgins in order to retain her youth. These stories have led to comparisons with Vlad III the Impaler of Wallachia, on whom the fictional Count Dracula is partly based, and to modern nicknames of the Blood Countess and Countess Dracula.
You may read more by clicking on the title of this blog post, which links back the the Wikipedia article.