The first mattresses were made of simple materials such as straw, feathers, and animal hair. They were stuffed into ticking covers which were filled with wool, hay or other plant material. These early mattresses had no springs and were not very comfortable to lie on. The purpose of these early mattresses was to keep people warm and provide a soft place to sleep. Over the years, improvements in technology allowed mattresses to become softer and more comfortable, and today modern mattresses are typically made from synthetic materials with built-in coils for support.