The nightgown or banyan was a style of casual 'undress' clothing popular among gentlemen during the 18th and 19th centuries, and heavily influenced by the loose styles worn in Persia and India.
This example is cut to a fashionable silhouette, with narrow waist and wide curving sleeves, although in fact it reuses a heavy floral silk of the type common a hundred years earlier. The amount of silk used implies that it came from a woman's open robe, and the wear evident to the fabric, even in the seams, would seem to suggest that it had been used heavily in the interim. In a time when fabric was worth more than labour and often recycled, this silk seems to have had at least three lives.