The pagan Robin was invented in 1984

Matter of the Greenwood Topic

Summary: Herne the Hunter appears in The Merry Wives of Windsor as a local Windsor ghost story and has no connection to Robin Hood until Richard Carpenter's Robin of Sherwood. Within a decade the mystical, green-man, earth-religion Robin was widely assumed to be the oldest layer of the legend rather than the newest. It is the same process Ronald Hutton documents for druids and for Arthur, happening fast enough to watch.