Magdalena Sibylla of Neidschutz

Magdalena Sibylla, called "Billa", was the daughter of Ursula Margarethe of Haugwitz, who had at one time been the mistress of John George III, Elector of Saxony. By order of the Elector, Ursula married Colonel Rudolf of Neidschütz, who officially appears as the father of Billa, though there were rumors that Billa was in fact the child of Johann George. If this had been true, it would have made Billa half-sister of her lover, John George IV.

Billa became mistress of John George IV in late 1691. By order of his mother, he was forced to marry, in April 1692, in an attempt to break up the affair. Instead, immediately after he assumed the Electorate, he openly lived with Billa, and she became the first ever Official Mistress (Favoritin) of an Elector of Saxony. John George abandoned his wife in the official residence and moved into another palace with Billa.

On 20 February 1693, Leopold I gave her the title Reichsgräfin von Rochlitz.

She had an illegitimate daughter with John George IV:

• Countess Wilhelmine Marie Friederike of Rochlitz (summer 1693 – after 1729): married to Count Peter Dunin and had issue.

She died in Dresden of smallpox, in the arms of John George IV, who himself became infected with the disease and died 23 days later.

• Böttcher, Hans-Joachim: Johann Georg IV. von Sachsen & Magdalena Sibylla von Neitschütz - Eine tödliche Liaison, Dresdner Buchverlag 2014, ISBN 978-3-941757-43-1.