La Belle Assemblée, June 1809.
Despite the title at the top of the print, this is not a promenade dress, but is described as Evening Full Dress. Perhaps it meant that one could promenade around the ballroom in this dress.
Note the armlets. (The description includes bracelets as well, but they are not shown. Neither is the described fan.) Throughout the Regency period, armlets and bracelets were always worn in matched pairs.
The print is described in the magazine as follows:
“EVENING or FULL DRESS. A white underdress of gossamer satin, embroidered at the feet and round the bottom of the sleeves with a laurel border of pale blue or pea-green foil. A Gallician robe, with demi-train of pale blue or pea-green crape, vellum gauze or leno; the edges finished with broad double foldings and cord. A full Circassian sleeve, looped with with Cornelian brooches and cord; loose triangular bosom, ornamented at the central point with a correspondent tassel. A short pointed drapery flowing from the right shoulder towards the knee, rounded on the left, and festooned near the bottom with bows or rosettes the colour of the robe. A small French tippet, or half-handkerchief of lace, thrown negligently across the back and falling over the left shoulder. The Austrian helmet hat of white satin, with laurel border and spray, in pale blue or pea-green foil; a round white feather, frosted with silver, drooping towards the right side. A gold elastic neck chain, with Maltese cross of Cornelian and pearl. Hoop earrings, armlets, and bracelets to correspond. Slippers of pale blue or pea-green kid, and [white gloves] rucked below the elbow. White Opera fan of crape, wrought in antique devices in silver.”