Magdalena Sibylla von Rochlitz, Reichsgräfin

Magdalena Sibylla von Neitschütz war Mätresse des sächsischen Kurfürsten Johann Georg IV., auf dessen Betreiben sie auch zur Reichsgräfin von Rochlitz aufstieg. Wikipedia DE

see http://en.wikipedia.org/wiki/Magdalena_Sibylla_of_Neidschutz.

By order of the Elector, Ursula married Colonel Rudolf of Neidschutz, 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.