From Wikimedia.
Charlotte Friederike's bodice has two visible halves as well as a floppy collar or bertha in this portrait, probably from after 1804.
Keywords: Charlotte Friederike of Mecklenburg-Strelitz, Mecklenburg-Strelitz family, Oldenburg family, curly coiffure, square neckline, bertha, waist band, Empire waistline, wrap