She was the illegitimate daughter of John George IV, Elector of Saxony, and Magdalene Sibylle, Countess of Rochlitz, his official mistress.
Her first two names, Wilhelmina Maria, were given in honour of the King and Queen of England, William and Mary; however, contrary to popular assumption, the English monarchs were not her godparents.
[2] Sir William Dutton Colt, the English envoy to Dresden since 1689,[3] was her actual godfather.
Her godfather having died when she was two months old,[3] she was raised at the royal court of her uncle and guardian, Augustus II the Strong, King of Poland.
In 1720 she married a Polish nobleman, Count Świętosław Piotr Dunin (died 1736), Castellan of Radom.