While I can find information about the von Helldorf family, I cannot find anything about Freiderike von Helldorf.
From pinterest.com/mama_stav/живопись-портрет/.
This is a good example of pre-Napoléonic dress worn to display the charms of a well-endowed woman.
Keywords: 1803, Graff, straight coiffure, U-décolletage, elbow length tight sleeves, Empire waistline, close skirt, wrap