The word mattress came from Arabic words meaning "to throw" and "place where something is thrown" or "mat, cushion." During the Crusades, Europeans slept on cushions thrown on the floor, and the word materas eventually became Middle English through the Romance languages. Commonly used by militaries to build forts.
Photo on a 1940 USDA circular promoting home production of cotton mattresses
Mattress Facts for Kids. Kiddle Encyclopedia.