In ancient times people slept on nothing but bundles of straw, animal skins and other natural materials. Sometime later, someone had the wonderful idea to raise this bedding off the ground to avoid drafts and crawling critters. Then came stone boxes, and in Egypt, the more important you were, the higher your bed was. Imagine having to climb steps in order go to bed. Talk about making an entrance! Later, we had beds made of fine woods, carved intricately or gilded  becoming even more a status symbol, later on the 18th century, iron came into play, one of the selling points being that insects could not penetrate iron. True!