Van wie was Wilhelmine, Gräfin von Lichtenau?

Wilhelmine, Gräfin von Lichtenau, born as Wilhelmine Enke, also spelled Encke (29 December 1753 in Dessau – 9 June 1820 in Berlin), was the official mistress of King Frederick William II of Prussia from 1769 until 1797 and was elevated by him into the nobility. She is regarded as politically active and influential in the policy of Prussia during his reign.