Hornbooks were most often made of oak, the letters were covered with transparent horn and the whole fastened down with brass strips and tacks. Sometimes leather was used to cover the wood or hold down the letters. Wealthy children had hornbooks made of ivory or silver. Schools used hornbooks made of brass or lead. The text consisted of the alphabet or the alphabet and numbers, or all of the above with the Lord's Prayer. Battledores were made of cardboard and later replaced hornbooks. They were cheaper to make and they often had pictures and reading lessons.