Mistress Sidonia, born Sidonia von Borek in 1550, was a noblewoman from Moravia, a region in what is now the Czech Republic. She was a member of the von Borek family, a prominent noble family in Moravia. Sidonia's life took a dramatic turn when she was appointed as a lady-in-waiting to Emperor Rudolf II's sister, Archduchess Elisabeth of Austria, at the royal court in Prague.

Sidonia's story has been documented in various historical accounts, literary works, and even operas. Her legend has endured, and she remains a fascinating figure in the history of witchcraft and the Renaissance.

Noblewoman, alleged witch, and lady-in-waiting

Sidonia was sentenced to death by beheading, which was carried out on a cold winter morning in 1583. Her execution took place in the Old Town Square in Prague.