
Muriel G. answered 10/17/20
Professional Archaeologist Teaching Social Science from the Ground Up
You are correct that underwear as we know it didn't exist, however, people in the middle ages did have undergarments for daily wear. Both men and women in most European countries throughout the medieval period wore shifts as the first layer of clothing next to their skin, which served to protect the more expensive fabrics they wore in subsequent layers from sweat and skin oils. Bed linens and especially mattresses were also quite expensive, so most people slept in their shifts as well, for warmth, to protect their bedding from sweat and skin oils, and to serve as an extra layer of defense from fleas, bed bugs, and other biting insects. Weather permitting, many people also did sleep naked. For more information about topics like this I highly recommend the YouTube channel The Ultimate History of Fashion, and the podcast Dressed: the History of Fashion, both of which have extensive archives about both men's and women's fashion.