The auction title is, "Princess Sophie of Thurn and Taxis, later Duchess of Württemberg, in lace-bordered white silk dress with pearls adorning her short sleeves, multi-coloured cashmere stole."
From artnet.fr/artistes/christian-wilhelm-jacob-unger/résultats-de-ventes; image size doubled.
Princess Sophie wears a bun set off by a tiara and a post-Napoléonic evening dress with a modesty piece-bertha in this 1820 Unger portrait.
Keywords: 1820, Unger, Sophie von Thurn & Taxis, Maria Sophia von Thurn & Taxis, Thurn und Taxis family, Württemberg family, Princess, Duchess, German, straight coiffure, bun, tiara, off shoulder bateau neckline, modesty piece-bertha, quarter length full sleeves, Empire waistline, close skirt, jeweled arm bands, cuffs, wrap