The tradition of the headless horseman goes back to ancient times, and examples of these phantoms can be found in the earliest German and Scandinavian folklore. According to legend, both rider and horse are said to be pitch black in colour and they can just as easily gallop in the sky as on the ground. The horsemen are sometimes said to be outcasts from the Wild Hunt, or otherwise great chiefs who had the misfortune to lose their heads in battle or were beheaded. A well-known Irish example is the Headless Rider of Castle Sheela, whose story is told in Ghosts in Irish Houses by James Reynolds (1947). Many literary critics have been interested in headless horseman legends and written book-length studies on this topic. Perhaps the most famous book on the topic is The Headless Horseman by American writer, Captain Mayne Reid, published in 1869 and based on an allegedly true case from Texas which the author himself had investigated.