Headless horsemen and coachmen are a spectre common to the British Isles. Usually dressed in seventeenth or eighteenth century clothing, they appear either riding at incredible speed, or silhouetted on the horizon. They remain attached to particular areas, some appear only on dark and stormy nights, others at a specific time every night. One famous story tells of Lady Howard's coach, built from the bones of her four dead husbands and driven by a headless man. It is rumoured to leave the gates of Fitzford, Devonshire at midnight every night. There is an old ballad that accompanies this tale.*
My Ladye's coach hath nodding plumes,
The driver hath no head;
My Ladye is an ashen white,
Like one who is long dead,
'Now pray step in, my Ladye saith,
Now pray step in and ride.'
I'd rather walk a hundred miles,
And run by night and day,
Than have that carriage halt for me
And hear my Ladye say,
'Now pray step in and make no din,
Step in with me to ride.
There's room, I trow, by me for you
And all the world beside.'
There are several basic background myths for these apparitions.
The probable explanation though, is simply that someone with a nervous disposition saw someone they didn't recognise with a high collar thundering down the road on a black horse and let their imaginations run away with them. Reports of them have almost disappeared in the last two centuries. Nevertheless, the image of the headless horseman is so striking that it remains a favourite of fiction.
*The poem comes from "Classic Devon Ghost stories," compiled by Paul White, the poet is unknown.