1762/5 Auguste Karoline, Duchess of Brunswick-Lüneburg by Johann Georg Ziesenis (location unknown to gogm)
Auguste Karoline of Braunschweig-Wolfenbüttel was born in 1764 and died in 1788. She was the daughter of Princess Augusta and was the first wife of Duke Frederick of Württemberg in 1780, age 15. They had four children. One of her sisters, Caroline, married the future King George IV of Great Britain and produced one child because her poor personal hygiene discouraged marital intimacy. Auguste Karoline's Wikipedia article is here.