Fashion history repeats itself. Sack gown to Watteau pleats to modern deconstruction of the sack gown.
Image 1: 1760s-1770s sack gown. Back view showing the two double box pleats. Also called a sack-back gown, sacque, or robe à la française. This would have been worn over a pair of stays, and hoops or panniers to support the skirt.
Image 2: 1890s tea gown. Back view showing Watteau pleats. Unlike the 18th century sack, tea gowns were informal, at-home wear. The bodice of tea gowns was often boned and the linings were fitted, even though the outside looks loose and flowy. Theoretically tea gowns could be worn without a corset. But, people were wearing these to receive friends at their home for tea, and not wearing a corset would likely feel similar to going bra-less today. I personally would feel a little too exposed having friends over with no bra, even if I'm otherwise in comfy, informal clothes.
Image 3: The Two Cousins, 1716 painting by Antoine Watteau. Pleated or gathered backs were called Watteau pleats starting in the 19th century, taking inspiration from the sack gowns depicted in Watteau's paintings. No one in Watteau's time or the rest of the 18th century would have called them Watteau pleats or Watteau gowns.
Image 4: Watteau, 1996 Vivienne Westwood evening gown, inspired by 18th century sack gowns, but with modern elements like the asymmetry of the trimmings and side-hoop pouf. The description from the V&A says this gown has double box pleats in the back, like the 18th-century sack gowns, but weirdly, does not seem to have a view of this gown from the back.
