The Headless Horseman of Linton

The Headless Horseman of Linton is a kindly ghost who has roamed the hills of the Yorkshire Dales for 600 years.
Many children in the area have told stories of how he let them ride his old horse.
But how did he come to be?
Set in the year of 1411. Guinevere loved two men, Cedric the wealthy son of the local land owner and Alfred who looked after the horses in the local tavern.
They both wanted to marry her, who would she choose and how is this connected to the start of the story of the Headless Horseman of Linton?