Gap Creationism, also called Restitution creationism or Ruin-Reconstruction, are terms used to describe a particular set of Christian beliefs about the creation of the Universe and the origin of man. The concept of the Gap Theory is widely thought to have been invented by Thomas Chalmers in the early 1800s, though some adherents maintain that it can be traced back to biblical times. Certainly it became quite popular when it was promoted by the Scofield Reference Bible in 1909.