Who washed clothes in the middle ages?
No one. Outer garments were never washed and underwear sometimes was washed. If it was worn by a peasant they did it, but the nobility had a serf do the laundry.
Middle Ages clothing and fashion, including the Medieval Kings Clothing, like everything else was dictated by the Pyramid of Power which was the Middle Ages Feudal System. Medieval clothes provided information about the status of the person wearing them. The clothing and fashion during the Medieval era of the Middle Ages was dominated and highly influenced by the Kings and Queens of the era. Only the wealthy could dress in fashionable clothes.