This Nightcap was made as a Birthday present by my good friend Julie back in 2009 you can see her blog about it here.
Nightcaps are basically beanie hats designed to keep you head warm in bed back in the days before central heating, also to reduce the spread of head lice after your wig was removed.
Nightcaps are said to be more commonly worn as people as got older probably because they are more likely to be bald or perhaps its because older people kept the fashion going as wearing nightcaps died out in the 1800's so its associated with older people your guess is as good as mine on that front.
Nightcaps where first reported has being worn in northern Europe in the middle ages and fashionable for all people from the mid 15th to late 19th Century.
Also known as a Sleeping Cap.