In high autumn toadstools constellate the woods, red and white, yellow and brown. The leaves lie among them like gloves of the dead.

There is a forest, or the remnant of one, that has been overlaid by county borders – Surrey, Hampshire and Buckinghamshire; but the forest does not know these invisible names – lines decreed by men. There is an oak amongst all the others, swag-girthed, limbs crazily angled, as if it has gone senile and is sprouting against all normal decorum. It is massive and lurches, in mid stagger, all alone in a clearing. The other trees stand in a circle, as at a respectful distance.

Here and there pieces of bark have fallen away revealing the white sap- wood. One bare patch is so large that it resembles a doorway. Ivory bracket fungus juts like steps up the trunk and one massive beam casts out across the space, making a reaching shadow, even in the crisp noon. Almost a yard along this beam is a worn ring. It looks polished, as if a rope was once fastened there and a heavy load swung out across the gap.

This is Herne’s Oak. Do not ask me where it stands. I will not tell you. Trees of the same name were planted by Queen Victoria and her playboy son Edward. These were mere fancies; a royal attachment to half forgotten lore. There have been many famous and illustrious men who have looked for this tree; yet, among them all, it was only Will Shakespeare who found it lurking in its musky glade. It was an old oak, even in his time – older, perhaps, than he knew.

The reason that royalty have held the image of this tree so highly in their imaginations is that it is reputed to hold a doom for them. If it falls they and their house will also fall. And because they have never found the true oak, they plant saplings that grow into false totems in and around Windsor Park. Meanwhile, with splendid contempt the true Oak thrives, in a slow sap-ticking time all its own, away in a neglected stand of the forest thatonce covered all England. There have been no axes here. These trees have never flinched at the sound of a saw. All the paths seem to veer away from this relic heartwood.

Let us suppose that, by chance, you do hack your way off the guide book trail, through the bracken and brambles, and get close enough to ponder the corrugated bark, the clawed branches and the ring-burned beam. Keep an eye on the November light as it needles through the woods. Turn away between two and three, before darkness begins to fall. Find the path and do not look back. I know you will.

The forest teems with clicks and snaps – the flick of a squirrel, a thrush in a thicket. The evening comes quickly, like a velvet sheet drawn over the bosk. A pheasant jirrs away from you. Its throttled cry tears the dusk. Of course you start. Of course you look behind. It suddenly seems a long way back to the pub car park, the stile and the laminated trail sign.

The sentinel trees stutter the dying light. Stop quite still. Back there in the glade something glints silver, as if a coin has been tossed in the gloaming. And what is that ‘notch-notch’ sound? A wind comes in the direction of the setting sun. It tries the collar and seams of your jacket. Turn from the wind and face the clearing. You can hear better with your mouth open. No cars hum in the distance, but there now is a heavy thump as a horse places its hoof. Then the unmistakable slink and chomp as it plays with the bit.

So here you are, standing open-mouthed, and there is a horse back there. It is a black and massive beast. You can see its haunches fractured by the trees. It is pacing the clearing, pawing the ground, snorting. You sense, rather than see it bucking its neck. You hear the trappings of its bridle. You want to cry out, to ask if there is someone there. But for some reason you do not speak. Instead you turn and strive for the path. The cold branches claw on either side. As your eyes begin to grope fear seems to hiss at you from every cleft and thorn.

‘Notch-notch.’ You suddenly place the sound. Antlers being sharpened, tested against a tree. It is, after all, autumn – the belling time. The horse continues to pace back there. Horse and stag? You fix on the fading eye of the red sun and aim for the car park half a mile away. Best not to run. You might snag your feet. Suddenly, there comes a yelp and whine of hounds crying in delicious anticipation. They are straining these dogs, their paws aching for the chase. The chase!

You run. Your legs are spurred by an urge so ancient it is deeper than fright. It is nameless and thoughtless. Your body reacts without permission or regard. You are running a narrow track. Twigs pull at your jacket, your hands, your face, but the scratches are painless. Only at the most tremendous crashing do you stop again and turn to look back.

A sight of deepest nightmare breaks from the stand of trees circling the clearing. Such a leaping picture is found only in the dim recesses of caves, where our ancestors splashed their fears across limestone in the colours of blood and charcoal.

A stallion, sleek as liquid tar, rears through the saplings, sending beech leaves upwards in a vortex. A rider, booted, bearded, huge, spurs the beast. His sword takes the red of the sun. The stark antlers of a king stag thrust from his head. At his side three dogs, the colour of washed coal, bay the rising moon. Their fangs are white. Their eyes are crimson slits.

You take all this in the second before you turn and hare down the path, running as you have never run before. You are oblivious to the breath itching like rust in your lungs. You are blind to the snares and snatches of cruel wood. In your eyes there is only the lowest bleb of sunset, in your ears only the pounding of massive hooves and the hounds singing for your flesh.

***

Say his name: ‘Herne’. It comes like a threat of frost across the tongue. Or a wind that sharps when the rooks pause calling and there should be a silence in the trees. Herne. Scholars have attempted to trace his story back, but the strands of his tale are like a run of weedy ground elder leading ever deeper into the forest. In his play, The Merry Wives of Windsor, Shakespeare gives us a few muscular lines concerning the rider in the woods:

There is an old tale goes, that Herne the hunter,
Sometime a keeper here in Windsor forest,
Doth all the winter time at still midnight,
Walk around about an oak, with great ragg’d horns;
And there he blasts the tree, and takes the cattle;
And makes milch-kine yield blood, and shakes a chain
In a most hideous and dreadful manner.

It is worth remembering that Will was once fined for poaching deer when he was a youth in Warwickshire. He knew the woods, knew the tawny heart of autumn. Windsor people would have told him the old tale:

Why, yet there want not many, that do fear
In deep of night to walk by this Herne’s oak.

In the inns they would have told him that many years before, back in King Richard’s time, there was a loyal keeper who accompanied his liege on deep forays to hunt boar and stag. One day they tracked spoor to a glade and there they came upon a white hart, ice-kissed and proud in the spring noon. The king drew his bow and shot, but the arrow went wide and caught the stag in the hind quarter. Blood fell on the snowdrops. The hart thrashed and roared. It lowered its tines and charged at the king, who stood transfixed and aghast. A shadow fell across his breast. It was his keeper, who had stepped in front to take the blow. Horn stabbed the keeper’s doublet, sheared into his ribs. Again, blood spattered the snowdrops. But he had drawn his dagger and the blade flashed at the stag’s white throat. This, they say, was Herne, who lay mortally injured under the hart, and had saved the life of Richard, his king.

They brought him back on the same cart on which the stag was thrown. Some say that a wizard appeared that night and ordered the hart’s antlers to be fetched to Herne’s bedside. The wizard tied the horns to Herne’s head and said that although desperately ill he would heal.

Sure enough, within a week he was strong again. The king, ever mindful of his reputation, promoted this Herne to head keeper. He returned to his work now dressed in a fine new hunting livery of deepest green, the envy of all the other keepers. But all was not well. Herne found that all his keen skills of tracking, his knowledge of wind and instinct for the direction of the herds had disappeared. At night he lay in his bed thrashing, as if in a fever. His dreams were all of chase and arrows and blood.

The other keepers, those jealous of his new livery and position, whispered to Richard; within weeks he fell from favour. The king dismissed Herne and banished him from the forest and parkland. Yet still Herne lingered there, particularly after dark, when the deer trod in slow state through the trees, under the white face of the moon.

And so it happened that one night the band of keepers found Herne standing alone in the very glade where he had saved the king’s life. They seized him, tied his wrists and slipped a noose over his head. They threw the rope over the beam of a sturdy oak at the centre of the glade and they hanged him. Laughing, they watched him kick and then they left his slumped body pendulous under the stars.

The next morning a young swineherd ran to the keepers and told them he had seen a man riding fast through the woods with antlers on his head and a pack of dogs at his heels. They went to the clearing and found an empty noose swinging in the wind.

At the fireside in the taverns the locals would have told Will Shakespeare how Herne’s fierce ghost roamed wide across the counties of Hampshire, Surrey and Berkshire, seeking his revenge on all who stand in his way. A particular curse of his is reserved for the descendants of Richard, the monarchs who have fenced and tamed the woods.

The bones of this tale may have been good enough for Will to hang with the sturdy flesh of his poetry, but the story of a horned rider from the depths of the wood seems to have more to it than the revenge of a hanged keeper. Antlers and a fiery steed? A hoary tree and pitch-dark hounds? Like the sneaking tendrils of ground elder that twine along unseen tracks, some people believe that Herne can be followed back much further than King Richard’s time, to ancient and unsettling origins.

***

‘Herne’; say the name again. It is like a sudden gust of snow on naked skin, or the trembling minute between two clouts of thunder. There are those linguists who have skills to untangle old languages. They see the name Herne as a worn smooth version of ‘Herian’, which in turn is derived from the old Norse ‘Einherja’. And here the chill begins to prickle at your neck. For ‘Einherjar’ means ‘Leader of the slain’ and is one of the guises of Odin the furious, Odin the smiter, Odin the fell god of the wilderness and mountains.

Odin, Wotan, Woden; all across the north of Europe, from the oak to the beech, from the ash to the pine, they used to worship him. When the English came to Britain their gods went before them into the forests and moors. Chief among them was their one-eyed, implacable Woden.

He is restless and vital, known for his trickery and cunning disguises. He has many faces, many forms, including this cold title: ‘Hangatyr’ – ‘God of the Hanged’. Accordingly, there is a verse in the old poem, ‘Havamal’, that tells of a weird and gruesome consummation:

I know that I hung on a windy tree
nine long nights …
… myself to myself,
on that tree of which no man knows …

On the sacred oak Woden sacrificed himself to himself. Pinioned there, he fretted against his own divinity. He was pierced by his own spear. As he hung against the bark, the branches wrapped around his legs and arms. Ivy crawled over his skin and thorns stabbed his flesh. Lost in his agony he looked inwards down the hidden paths of his mind. Then on the ninth night he came down from the tree with knowledge. In the wilderness of his torment he had gained the secrets of the runes. For it was Woden, so our ancestors believed, this God of the Hanged, who brought writing to mankind.

***

Hunters give clear whistles and shrill cries. They favour brass horns of high clarion. You can shout in a forest and the sound will blunt against the trees. How much more so with whispers? In November the leaves purse on the wind and one man conferring to another will find his tale taken and twisted. Stories pass down through centuries and sussurate against the years. The stories change. A Teutonic hanged god transmutes to a tale of a king, a white hart and a wronged keeper. Yet the sap of the truth can be tapped, and Herne, the ‘Leader of the Slain’, canters towards us in one more dread aspect.

***

You are still running. The forest hunches in the smoky new darkness. The roots and branches still hiss at your limbs. The growing weakness in your chest must be denied if you are to gain the car park. Behind you the undergrowth thrashes and the hounds leap every fallen trunk in slavering joy. The horse plunges and the horned rider bends low with his mailed hand open, ready to snatch. He is literally at your heels.

You break onto the tarmac. Your Peugeot sleeps over by the wall of the pub. There are no lights on; no smoke from the chimney. The pub is closed. It is over. You trip, falling first on one knee, and then you feel the gravel bite your cheek. It is over. A hunted fox will run and run, but sooner or later it will fall, and then, ribs heaving, tongue lolling, it will turn and await the pack.

***

From the carved homesteads of the Schwarzwald to shepherd huts in the Tatras Mountains, from rain-soaked cottages in the Cumbrian Fells to Basque villages under the crags of the Pyrenees there are tales of a relentless huntsman and his pack of hounds. In Germanic and Nordic lands they are known as the Wild Hunt. A horned rider gallops the midnight sky, through bogs and vaulted glens. His prey is any traveller foolish enough to let darkness overtake his steps. More explicitly it is the wicked and those with guilty secrets who have the most to fear.

Everywhere the stories tell that the huntsman rides sinners down in lonely

places. He grabs them by the scruff of the neck and carries them up into the shivering heights. The victim dangling at the pommel of the saddle might look behind and see the dogs coursing at their master’s side. How they yelp and gnash in ecstasy. Behind them he might see other riders – gaunt figures with parchment skin and dreadful eyes. Moonlight picks out their horned helmets and tarnished breastplates. The dead ride in Herne’s train. He is, after all, ‘Einherjar’ – the Leader of the Slain. The victim is bound for hell.

***

The stallion rears over you and when its hoof comes down sparks flash on the frosty gravel. You are on your back cringing. Your jacket is torn. The rider leans towards you across his creaking saddle. His horse snorts and shudders. He holds the dogs back with a sweep of one gauntlet. They snap and growl in disappointment. His black beard is woven with ivy. His antlers flutter with velvet rags. His eyes hold nothing. They are empty. He speaks but no words are audible. His speech comes in an icy furl. He shouts noislessly and sudden rime crackles on your scratched cheek.

Then comes a moment more awful than all the preceding ones. He fixes you with his oblivion stare and sharp silence creeps over you. You cannot think. Terror floods your ears, your mouth. Say whatever prayers you can remember.

He straightens and looks about himself, looks up to the new stars. He points with his red sword and suddenly kicks his spurs. The horse rears again, but this time it does not descend. Instead it lifts. Impossibly the horse gallops upwards, bearing the huntsman over the tiled roof of the pub. The hounds follow, chasing on the air above your head. Their eager baying fades on the wind. Herne does not want you. You have been lucky.

Steven O’Brien’s retellings of British and Irish myths will be published by Greenwich Exchange in 2012.