I’ve been away too long.

The plane took me from London to Dublin in less than an hour. I would have come this way before if I had known how simple it was. When I first took the boat to England, vomiting up my whole self into the Irish Sea, I swore I’d never go back. But most promises wear out in the end. This plane trip was almost merry, clouds back-lit by champagne.

I bought it in honour of Petronilla. Since she couldn’t be here today it seemed only fitting to toast her virtues in overpriced bubbly, ten thousand feet above the island she never left.

The rented Volvo took me to Kilkenny with surprising speed. They’ve built craft shops on every corner, and knocked down a lot of old houses. Kyteler’s Inn is still there, though; its wooden lines stand firm against the swarm of tourists. There’s an Alice’s Restaurant in the cellars (‘It’s a kind of magic!’ jokes the sign, catching the sunlight), and upstairs is called Nero’s; how very suitable. What’s your poison, traveller?

I stand at the bar and order a glass of the best red they have. I look around, waiting for the centuries to fall away, but my eyes lodge on the chintzy little tableclothes and chairs. I am so used to the twentieth century that it is almost impossible to imagine myself back to the fourteenth. Hard to believe that this round-bellied building was ever cold and damp, with one fire sighing and the smell of tallow flaring in the nostrils of visitors.

I peer at the wall, where a Disney hag pours cups of smoking brew for four little men with uneasy expressions. Perhaps they have noticed that their shoes, toes tied to their knees, are from the wrong country and century. I read through the five-line caption, which is a tribute to the powers of invention. Nothing worth losing my temper over. Why should anyone remember, anyway, except someone like me whose business it is?

There’s been a lot of water under the bridge since 1324. History always becomes a cartoon, where it survives at all. Your best hope for a ride towards posterity is the bandwagon of folklore.
‘Oldest house in Kilkenny, this is.’
I accept the wineglass from the greying woman behind the bar. ‘So they say.’
‘You know the story?’
‘Oh yes.’ I take a sip: not dry enough. I wonder what kind of hash this woman could make of the tale, but it hardly needs another telling. It is remarkable only for the gender of the protagonist. When a man kills his wife, he is a tortured rebel, criminel de passion, dusky Othello or bluff King Hal. When a woman kills her husband, she is never allowed to forget it. I stare at the drawing again. Alice Kyteler, four times widowed in two dozen years, has evolved into a long-nailed monster, a Kilkenny Clyternnestra.
My eyes swivel back to the barmaid, who is polishing glasses with a Guinness tea towel. ‘Beg your pardon?’
‘Doing a radio programme or something? Family history?’ she adds. Her hand has paused, knuckles yellow against the glass.
‘More or less,’ I tell her, with a ghost of a smile.
‘Very nice.’

I glance back at the wall beside me, then at the others, weighted down with old maps and giant replica copper pots. No picture of Petronilla de Meath. I suppose I could ask the barmaid, but I’m not sure if my mouth could bear to form the words.

Why is it that almost nobody knows Petronilla’s name, when she was so much more remarkable than her mistress? No demon Dame Alice called up and bound with spells ever served her so faithfully. What interests me is not so much the mistress’s evil, which seems after almost seven centuries to amount to no more than a banal footnote in the annals of war and treachery, but the maid’s extraordinary ordinariness. How through thick and thin, sickness and sin, Masses read backwards and Christian funerals, Petronilla retained her sense of being a good servant, whatever that could mean in a house like this one. As if she had heard some fireside tale that ended with the tag, Whanne that yr mistresse sell here soule to Luciphere ond take a wisshe for to kille her lawfulle wedded husbandes, be you of gode cheere ond giff her al manere of aide for to brewe ye

‘I love history, myself.’
I turn on the barmaid, who is rubbing at the lipsticked lip of a glass. ‘Why is that?’
Her blue eyes, behind her glasses, seem surprised by the question.
‘Well, it makes you feel more complete, doesn’t it?’ A pause. ‘Knowing where you’re from.’
‘Does it?’
‘Reminds you there’s more to the whole business than your own little life.’ She gives me a wholly unmerited smile. ‘I like to think that no one ever really dies as long as their folks remember them.’
‘Perhaps they’d prefer to.’
‘Remember them?’
‘Oh. Oh I don’t think so,’ says the woman, as if to reassure us both.

I ask to be directed to the Ladies; this seems the best excuse for poking around. For all the dark wood, most of these walls look new; these smooth beams have never had a sconce stuck in them. I hitch up my tights, careful not to tear them. I take off my heavy ring to wash my hands. My face looks back at me with a hint of defiance: no new lines today. On the wall, a Kondo-Vend machine offers me the Quality Range of Luxury Lubricated Sheath Contraceptives. I can tell I won’t find what I’m looking for in Kyteler’s Inn.
As I cross the narrow elbow of St Kieran’s Street, I find myself humming a tune, a very old one; I realise that it has been stuck in my head since Dublin. The words slide onto each other like water over worn rocks. Voice on anonymous voice, disciplined in melancholy resignation.

Quiconques veut d’amors joi’r
Doit avoir fay et esperance

Such patience the singers had back then, giving every melancholic syllable its own line of music, a full half minute to a phrase, as if they had all the time in the world. Faith and hope are what the seeker after love must have. Faith to keep you longing, hope to relieve your despair.

The town has become a maze of gift shops and boutiques; I can’t tell where anything used to be. As I step off a kerb, a car roars by, inches from my handbag. Labhair Gaeilge, says the bumper sticker, as if simple encouragement could set my tongue to talking the language I’ve long forgotten.

What was Petronilla’s first name, I wonder? The one she knew herself by when she was a raw serving-maid who could speak only two tongues and both of them with a County Meath accent. When her hair still fell loose under her white coif, not yet having been tucked away as the mark of womanhood. When she came in a cart to Kilkenny, telling her beads, before her mistress renamed her for the saint whose day it was, the Roman Virgin who tended Peter. What went through the girl’s head those first months, I wonder, as she ran to order: ‘Fetch my Venetian brocade, the rayed one, you fool,’ and ‘Strap on my pattens if you would not have me wade through every puddle in town,’ and (in a low voice) ‘Have you fetched candles of beeswax for the ceremony?’

She was Dame Alice’s loyal bondswoman from the start; she was a dagger thrown back and forward between those ruby-weighted hands. The first Sabbath made her retch in a corner, but she said nothing, told no one, never broke trust. The girl had no malice of her own, but her mistress’s orders girded her like chainmail, and obedience made her brave.
The most inexplicable thing is that at no point in her imprisonment or trial did Petronilla try to run away. Did she keep hoping Dame Alice would return from England to burst the doors, with all the force of law or simply a click of her stained fingers? Or did the maid simply keep her garbled faith, offering herself as ransom for her vanished mistress, waiting on the pleasure of the dark master? Or, more likely, did some portion of her drugged conscience feel her execution to be a proper end to the story?

What is clear is that she was not one of the weeping, piteous victims who flock across the pages of history. She embraced her death as a final order. Does that make her mistress’s betrayal better or worse? All the records have to say on the matter is that at the hour of her death, Petronilla declared that Dame Alice was the most powerful witch in the world.

I feel slightly faint. I am standing on a street comer with a slightly crazed expression. A small girl leaning against a lamp-post watches me; she has a purple birthmark the shape of a kidney. ‘Lights changed ages ago, Mrs,’ she points out.

I cross, without answering her. I should be looking for the gaol, but I can’t face it yet. I wander up the hill, past Dunnes Stores, a stall selling local fudge, a poster inviting costumed revellers to a Quentin Tarantino Night.

St Canices’s seems almost small after the great cathedrals of England. Its walls are grey and serene; beside it, the round tower pencils the clouds. I look for the grave, but they must have moved it. Inside the church I finally stumble across the headstone, one of a dozen propped against the walls. With difficulty I make out the old French letters framing a fleur de lys cross. Here lies Jose de Keteller, they say, Say thou who passest here a prayer.

He came to this town in chain-mail with a long sword, an old-style legitimate killer. Learned Gaelic, grew long moustaches, finally even rode without a saddle in the native way. A peaceful settler, shaping himself to the island fate had placed him on, Jose de Keteller was not to know how his name would be immortalised by his iron-willed daughter. Why is it so much worse to execute husbands than infidels, I wonder? Most of us are descended from killers, one way or another.

None of this is telling me anything I didn’t already know, and my feet are beginning to ache. In the museum, I take my shoes off for a moment to stretch my feet on the smooth wooden floor. What a motley collection we have here: grisset and candle-mould, cypress chest and footstool, a copy of a will specifying what a certain widow would inherit from her husband if she did not remarry or have carnal knowledge of any man willingly (this last bit makes me smile), and a deer skull with antlers six feet wide. On a dusty shelf I find a huge metal tongs, for stamping IHS on holy wafers. My heart begins to thump again.

Downstairs in the bookshop, I calm myself with a collection of photographs of Irish lakes. The girl assesses me as a browser, and turns back to the phone, demanding (in an accent that I have not heard in a long time) to know who said she’d said she fancied that spotty eejit. I tum the pages, recognising the heads of birds. I move on to the small history shelf, where I learn that the town’s most famous witch was, in fact, framed.

‘Alice Kyteler (possibly a misspelling of Kettle, a fairly common English surname),’ I read in one hardback, ‘was a victim of a combination of the worst excesses of fourteenth-century Christo-patriarchy. Threatening to men by virtue of her emotional and financial independence, this irrepressible bourgeoise, who always kept her maiden name through repeated widowhoods, aroused the hostility of avaricious relatives and a misogynistic Catholic establishment. As in so many other “witch trials,” powerful men (both church and lay) projected their own unconscious fantasies of sexual/satanic perversion onto the blank canvas of a woman’s life.’

I can’t help smiling: blank canvas, my eye. There is a grain of truth there, of course: before she ever trafficked with darkness, the citizens of Kilkenny resented the Kyteler woman’s fine house, bright gowns, every last ruby on her fingers. But that does not make her innocent.

The girl on the phone is eyeing me wearily. She is letting her friend speak now, the faraway voice winding down like clockwork.

How the twentieth century loves to issue general pardons. At this distance, it cannot distinguish the rare cases of serious evil from those of farmer’s wives burnt by neighbourly malice. Dame Alice should not be lumped in with the victims. She was the real thing. She could be said to have deserved the punishment she never got.

Unlike Petronilla, not mentioned in the historical analysis. Petronilla, who should have been set free when the whole sorry mess was concluded. Why could she not have been shaken out like a wide-eyed cat from a sack, to run across country and live some ordinary life?

It is too hot in here, all at once; too cosy, with a tub of Connemara Marble Worry Stones going cheap beside the till, and remaindered Romance stacked high on a table between the symmetrical stares of Decor and Archaeology. I replace the books neatly and leave.

Outside it is cooler, at least; the edgy breeze of late afternoon fills the town. I walk along the main shopping street, wondering where the gaol could have got to. A hamburger carton impales itself on my heel; I kick it off. My toes feel crushed; my head is beginning to pound.

Anything could have been built on the site of Petronilla’s last months: a hardware shop, a B&B, a public toilet. A gaol is by nature anonymous; all it requires is four walls or a hole in the ground, a barred square of light if you’re lucky.

I pause outside a pub offering Live Trad To-Nite. I stare at the five bars just above ground level, the darkness behind them. All they hide is a cellar of beer barrels, but if I close my eyes I can almost see her pallid hands caressing the iron. Petronilla in the shadows, crouched in her dirty smock, once good linen, a present after her first year of service. A face like a drop of honey, looking out of a bedraggled wimple – unless they shamed her by leaving her head naked. Did her pale hair come down at last, escaping coif and cap and veil, falling back into girlhood?

I rest my palms against the pub’s grey slate, ignoring the glances of passersby, and try to conjure up the rest of her. Would there be marks of torture, the tell-tale insignia on wrists and soles? Probably not; there would have been no need, since she seems to have told the whole story freely once her mistress had escaped to safety. Besides, they probably preferred to bring the girl unmarked to the stake, a perfect sacrifice to the fire-breathing dragon. Where would they have done it, I wonder – outside the gaol, outside the city walls, or in the busy thoroughfare of the market square? Which supermarket sits on Petronilla’s ashes now? Pressing my fingertips so hard against the cement that they turn grey, I ask every question I can think of. Was there anyone there that day who, remembering alms or a kind word or just the turn of her cheek, had enough mercy on her to add wet faggots to the kindling? Was there enough smoke to put her to sleep before flames licked the arches of her feet?

This is one of the times when I wish I still had the ability to cry.

Petronilla is not here. There is nothing left. I do not know what I was hoping for, exactly: some sign of presence, some message scratched for me on the prison wall, some word from her walking ghost. I shut my eyes more tightly, but all I can hear is an inane pop song leaking from a taxi window. Hold on, the singer begs, Every word I say is true. Hold on, I’ll be coming back for you.

I let go of the wall; the pads of my fingers are scored and pock-marked. As I stare at them they plump into their usual shape. The daily miracle, the return to the same healthy flesh. How long must it go on?

I stride back to my car, through a crocodile of French schoolchildren; in the car park, I have some difficulty remembering what colour I rented. Automatically I fasten my seat belt. I have never tried to kill myself; I am afraid to discover that it would not work. I shrug off my shoes and lean my head back on the padded rest. What on earth am I doing here?

My ring is cutting into my finger; I pull it off and stare at it. Rubies to stave off disease; this is my last one. Once in Birmingham someone tried to mug me, and I cracked his nose with this ring.

Time has not absolved me of anything. The clothes have been transformed, the name is different – I change it every fifty years or so – but the face in the rear-view mirror is the same. And in almost seven centuries of exile I have not managed to forget Petronilla.

It is almost funny, is it not? One would think that a woman who in her esoteric researches had stumbled across the secret of immortality would feel free. Exhausted by life’s repetitions, yes, starved for fresh food, tormented by the bargain she made, but in some sense free. To wander, at least, to move, to leave behind the quarrels of mortals. I never expected to be so haunted by one face that I would have to make my way back to Kilkenny.

More than any husband or lover or child; more than anyone I have hurt since I went into exile; more than anyone I left without warning (when they wondered why I was not aging) or killed with my bare hands (when they deserved it), Petronilla’s is the only death I still regret. Leaving her behind was the worst thing I have ever done.

I did no harm to my first husband, the richest moneylender in town; I bore him a son and fed him titbits on his deathbed. As for my second, in my grandmother’s time I could have followed the old ways and left him after a year and a day, but under Common Law I was his for life, to stamp his mark on. I bent under his weight like a reed, and in the pool of humiliation I brushed against my power. He was sick already – the beatings were getting feebler – but the poison sped him on. My third … yes, I remember. I despatched him in a night, after I caught him in the linen-cupboard ripping the skirt off Petronilla. The night before his funeral I dropped his heart in the River Nore.

As for my fourth, John le Poer, he was a loving man who shut his ears to the rumours circulating about me. But by then, you must understand, I had signed with my own blood, and the sacrifice was called for. His hair came out in handfuls, when I brushed it at night; his nails began to bend backwards. Petronilla never claimed to understand the rituals, but she knew that whatever Dame Alice said had to happen. When John, made suspicious at last by the gossip of my dead husbands’ disinherited children, talked to Bishop Ledrede, it was my faithful maid, my flawless echo, who repeated to me every word they had said. When my husband wrenched the key from my belt and burst into my room, finding and forcing open the padlocked boxes, I kept one curious eye on Petronilla. She wept because the story was almost over, but she showed no shame.

I was charged along with eleven accomplices, most of whom barely knew me to see. The seven charges told of dogs torn limb from limb and scattered at crossroads, fornication with Ethiopian hobgoblins, and a dead baby’s flesh boiled in a robber’s skull. The grease I used to keep my face soft was listed as a sorcerous ointment for the staff on which I flew across Kilkenny town by night. Bishop Ledrede was widely read, and had a vivid imagination. He was not to know that power is composed of simple elements, once you have stumbled across it.

Ledrede did not do it for the money his spiritual court could hope to confiscate; like myself, he was motivated by wrath and glory. And so, when I had indicted him for defamation and sailed to England with all my jewels, when my son William had agreed to pay for the reroofing of St Canice’s as a penance, and when the other accused accomplices had melted into the night, then the Bishop focused his gaze on Petronilla. She was all he had left.

It was not that I could not have brought her with me, torn her out of prison somehow; I simply never thought to. That is my crime; that in the urgency of my flight, full of the sense of my own devilish importance, I did not even condemn my maid deliberately, but carelessly, as I might have said, ‘Pick up that sarsenet gown.’

I have had plenty of time to think of her since. In almost seven centuries of wandering I can make an informed comparison: I have met no one who loved so well or was so betrayed. She was not a natural killer: she ground poisons together out of mute loyalty, and what purer motive is there than that?

It is so long since I have killed, I have almost forgotten how. It is not worth risking nowadays. They lock you up, take down what you say and never put an end to it. Oh Petronilla, how I envy your death. Not the manner of it, the pain and squalor, but its definition. How it took you by the hand and led you away before your bursting youth could dwindle.

Unless I am casting a web of glamour over the story to lessen my guilt? But that is not how it works. My envy and my guilt pin each other down. Petronilla’s, short and powerless, is the life I did not lead, and cannot lead no matter how long I drag on, and will never fully understand. Petronilla’s exultant face I cannot leave behind me. She follows, just out of view, and all the rippling voices are hers.

Quiconques veut d’ amors joir
Doit avoir fay et esperance

Having had faith and hope enough to last her short lifetime, did it come down to love in the end? Was that what she feasted on, among the rats in Kilkenny gaol? How could I be loved by such as her?

For all my sheer elastic skin, I am a hollow woman. My ribs are an empty cauldron now; my breath couldn’t put out a candle.

I start the car. My one faith is that I will find some trace of Petronilla. My one hope is that she will teach me how to die. My one love now, the only one whose face I can remember. There, around some corner, she burns, she burns.