Broadly speaking, at times when the bonnet was popular as female headwear, so were caps. Generally caps for women were meant to be worn inside the house and made of linen or other undergarment materials. Designs covered the hair and they were considered especially suitable for married women and members of the bourgeoisie (Clark, 70). The great importance of indoor caps for middle-class women is visible in novels like Cranford which is set in the 1830s. Whenever a visitor would require a change into a better dress, the women of Cranford would change their caps. They were so popular that “[t]he expenditure on dress in Cranford was principally in that one article” (Gaskell, 80). By the end of the Victorian period the caps had lost their appeal to younger women. After the 1870s they were worn only by women past their middle age. Madame Marie Bayard mused in her 1876 book on The Art of Beauty that it is “a pity that caps are so entirely forgotten by young people. They seem to be considered only fit for servants and great grandmothers.” (Bayard, 21). The cap would, however, appear once more on the fashion stage during the 1910s and 1920s under the guise ‘boudoir cap’, before departing the world of lingerie in 1930. The shape of the garment changed and became closer fitted to the skull with frills and decorations framing the face and concentrating around the ears.
Considering both the colour scheme and the type of garment, boudoir caps do appear to be stylistically out of place in the time they were most widespread. Regardless, they were immensely popular because they were able to fulfil several social and emotional functions that went far beyond their practical use of preserving hairstyles overnight.