The (True？) Medieval Ghost Stories of William of Newburgh

Ghost stories aren't a modern invention -- they've been around for a long time, but rarely were they written down in historical works. That's not the case with William of Newburgh, an Anglo-Saxon historian from the 12th century, who recorded several tales of the walking dead, which he regarded as true -- or at least true enough to fill the space between the machinations of kings in medieval England.