She was the official royal mistress of Charles I, Landgrave of Hesse-Kassel in 1711-1730, and the political adviser, first lady and head of the court of William VIII, Landgrave of Hesse-Kassel between 1730 and 1756.
After the death of Maria Amalia of Courland in 1711, she became the official mistress of Charles I.
She had a good relationship to his sons, and after his death in 1730, she was allowed to remain at court.
She became the head of the court of William in 1730, and because his consort Dorothea Wilhelmine of Saxe-Zeitz was imprisoned due to mental illness, she acted ceremoniously as the first lady of the court.
In 1742 Barabara Christine was awarded with the title of Imperial Countess by Charles VII.