1816 Countess Grosvenor by Sir Thomans Lawrence (location unknown to gogm)
Born in 1797, she was the daughter of the infamous Duchess of Sutherland. Her article in thepeerage.com is here.
From Wikipedia.
Countess Grosvenor wears a dress similar to that worn by Countess of Blessington for her Lawrence portrait, but with diaphanous over-sleeves. She wears something like a modesty piece to convert a sqaure décolletage into an even more alluring sweetheart décolletage in this 1816 Lawrence portrait.
Keywords: 1816, Lawrence - Thomas, Sutherland family, Grosvenor family, Countess, British, bun, sweetheart neckline, modesty piece, quarter length puffed sleeves, waist band, Empire waistline, close skirt, over-sleeves, ruffles, long full sleeves, cuffs, brooch