1677, Morocco. Behind the magnificent walls and towering arches of the Palace of Meknes, captive chieftain's son and now a lowly scribe, Nus Nus is framed for murder. As he attempts to evade punishment for the bloody crime, Nus Nus finds himself trapped in a vicious plot, caught between the three most powerful figures in the court: the cruel and arbitrary Sultan Moulay Ismail, one of the most tyrannical rulers in history; his monstrous wife Zidana, famed for her use of poison and black magic; and the conniving Grand Vizier. Meanwhile, a young Englishwoman named Alys Swann has been taken prisoner by Barbary corsairs and brought to the court . She faces a simple choice: renounce her faith and join the Sultan's harem; or die. As they battle for survival, Alys and Nus Nus find themselves thrust into an unlikely alliance - an alliance that will become a deep and moving relationship in which these two outsiders will find sustenance and courage in the most perilous of circumstances.

From the danger and majesty of Meknes to the stinking streets of London and the decadent court of Charles II, The Sultan's Wife brings to life some of the most remarkable characters of history through a captivating tale of intrigue, loyalty and desire.

The rain has been coming down hard since the early hours, turning the ground to a quagmire. It beats on the roof tiles and on the terraces where usually women hang out washing and spy on the comings and goings of the men below. It beats on the green faience of the Chaouia Mosque and on the four golden apples and the crescent moon atop its tall minaret. It streaks the walls surrounding the palace with dark stains like blood.

The artisans stand with their robes plastered to their bodies, staring at the massive slabs of cedar for the main gate, now sodden and mud-spattered. No one thought to protect the wood against rain: this is the time when marigolds should carpet the scarred red hills like drifts of orange snow and figs begin to swell in city gardens.

A continent away, the French king is engaged in extravagant plans for his palace and gardens at Versailles. Sultan Moulay Ismail, Emperor of Morocco, has declared he will construct a palace to dwarf this Versailles: the walls will run from here in Meknes for three hundred miles over the mountains of the Middle Atlas all the way to Marrakech! The first stage – the Dar Kbira, with its twelve towering pavilions, mosques and hammams, courtyards and gar¬dens, kitchens and barracks and koubbas – is nearing completion. The Bab al-Raïs, the main gate to the complex, is to be inaugurated in a day’s time. Provincial governors from all parts of the empire have arrived for the dedi¬cation, bringing with them presents of slaves, cloth-of-gold, French clocks and silver candlesticks. At midnight Ismail plans to slaughter a wolf with his own hands, set its skull in the wall and bury its body beneath the gate¬way. But how, if the door itself – symbol of the entire grand enterprise – is not finished? And what will the sultan do if his plans are thwarted?

At least one of the artisans is contemplatively feeling the back of his neck.

Across the compound a group of European slaves toils away on top of the outer walls, repairing a monstrous hole where there has been an over¬night collapse. The pisé is waterlogged: the sand and lime were probably not correctly cured in the first place, and now the rain has made it fatally unstable. No doubt the repair will fail too, and then everyone will be flogged for negligence. Or worse.

The workers are meagre of flesh and pale of skin, their faces sharpened by hunger, their tunics ripped and filthy. One of them, heavy-bearded and hollow-eyed, gazes across the desolate scene. ‘God’s bones, it’s cold enough to kill hogs.’

His neighbour nods glumly. ‘As grim as Hull in winter.’

‘At least there’s ale in Hull.’

‘Aye, and women.’

A general sigh.

‘Even the women of Hull look good to me after five months in this place.’

‘And to think you went to sea to get away from women!’

The laughter this remark provokes is brief and bitter. Survivors of months in the stinking underground matamores in which they have been confined by these foreign devils after being seized from merchant vessels and fishing boats from Cork to Cornwall, they have spent their first weeks in Morocco telling their stories to one another, keeping the dream of home alive.

Will Harvey straightens up suddenly, pushing his rain-slick hair out of his face. ‘Christ’s eyes, will you look at that?’

They all turn. An inner door within the great palace door opens and an odd contraption pokes out, followed by a tall figure that has to bend almost double to exit, then draws itself up to an exaggerated height. It wears a scarlet robe partially covered by a white woollen cloak with gold borders. Above its turbaned head it holds a round testern of cloth on a long handle which shields it from the driving rain.

‘What the devil is it?’ Harvey demands.

‘I believe it’s a bongrace,’ ventures the Reverend Ebslie.

‘Not the implement, you dolt: the thing that holds it. Look at how it picks its way like a trained Spanish pony!’

The figure moves gingerly between the pools of standing water. Over its jewelled slippers it wears a pair of high cork pattens at which the mud sucks greedily. The workers watch its progress with growing fascination and soon begin to catcall:

‘Clownish fool!’

‘Catamite!’

It is a rare pleasure to pass a fraction of their torment on to another, even if their target is a foreigner and does not comprehend the insults.

‘Mincing coxcomb!’

‘Lily-white quean!’

‘Half-and-half!’

As if this last and most innocuous remark has found its mark, the figure suddenly halts and, tilting the ridiculous contraption back, gazes up at them. If its demeanour and clothing have given the appearance of wilting femininity, the face that is turned up to the hecklers gives the lie to that impression. Lily-white it most certainly is not; nor delicate either. It looks as if it has been carved out of obsidian, or some hard wood blackened by age. Like a war-mask, grim and immobile, it gives no sign of the human beneath – except that a warning line of white shows under the black iris of the eye as the man’s gaze scorches over them.

‘You should be more careful whom you insult.’

A shocked silence falls over the group of slaves.

‘One click of my fingers will bring your overseers running.’

In the shelter of a doorway some thirty yards away four men are brewing up a samovar of tea. The vapour from the pot wreaths around them so that they look like wraiths. But the impression of insubstantiality is deceptive: given the opportunity to dole out punishment they would abandon their tea-making in an eye-blink and come storming into the world of men, whips and cudgels at the ready.

The prisoners shuffle awkwardly, too late realizing the gravity of their error. No one else speaks English in this godforsaken country!

The courtier regards them dispassionately. ‘Those men have been chosen for their ruthlessness. Not an ounce of common humanity remains to them. They are instructed to punish the lazy and the insubordinate without mercy and will kill you and bury your corpses in the very walls you are rebuilding without any regret. There are always more to take your place. Life is cheap in Meknes.’

What was your inspiration for the book?

My third Moroccan novel is THE SULTAN’S WIFE, a little-known chapter of Moroccan history set at the court of Moulay Ismail, the sultan whose glittering empire stretched from the Atlantic and Mediterranean coasts of North Africa all the way through the desert to Timbuktu, who sent an embassy to the court of Charles II in 1682. It was inspired by a conversation Abdel and I had in a restaurant in Agadir where they had a print of Delacroix’s famous portrait of a Moroccan court slave – Turk in a Turban – on the wall. It was the look in the subject’s eye that caught my attention: he was a black slave, and no doubt a eunuch (since all male attendants in the inner court would have been castrated in order to guarantee the validity of succession) and yet he looked so proud. Abdel told me that when the last King of Morocco, Hassan II, died in 1999, his bier was borne out of the palace in Fez by six of his most cherished ‘servants’: all black, and all having spent their entire lives within the palace walls. This would have been the first time they had set foot into the outside world, to carry their king to his last resting place. [nb. Slavery was abolished in Morocco only in 1960: my mother-in-law remembers having slaves in the household. A man cost a bucket of salt; a woman a dish of salt.] And so the central character of THE SULTAN’S WIFE, Nus-Nus – the Arabic word for a half-and- half coffee – was born. A man taken captive in the jungles of West Africa during internecine tribal feuding, sold as a slave and castrated as a gift to the all-powerful sultan, who had come to the throne by ruthless and bloody means, and held the reins of power in the same manner for all his long life.

How closely are your characters and settings based on fact and how much is fiction? And how much do you research?

All the known characters – the sultan, his chief wife and her sons; ben Hadou, Charles II and his wife and mistresses; the members of the English court, and of the Royal Society – are all fully historical and based on as much good research as I’ve been able to read and absorb. Nus-Nus is my own creation.

Researching for historical novels is all-consuming if you’re going to properly immerse yourself in the period. I spend the best part of a year researching each of these novels: visiting the places involved – in this case, the imperial cities of Morocco – Fez and Meknes – scenting the air, tasting the food, talking to the people, walking the ruins, admiring the artistry of the culture, taking photos, visiting libraries and scholars, looking, looking, looking…

I read everything I can lay my hands on, too: in French and English, and my husband Abdel reads for me in Arabic. I buy obscure books -- such fun trawling for them in antiquarian bookshops: my favourite is RITUEL ET MAGIE DU NORD AFRIQUE – Ritual and Magic of North Africa – published in the 19th century. It cost me a small fortune, but proved invaluable not only in giving me specific spells and ingredients, including the hand of a dead child (don’t worry: was not tempted to see if they worked), but in sparking ideas, since Ismail’s chief wife Zidana was also known as ‘The Witch’ and practised all manner of terrifying rituals out of her native West Africa (probably Cote d’Ivoire). I go to the British Library for primary sources like ambassadors’ journals and to the Kew for the Court records of the time.

Only when I have read to a reasonable level of understanding of the period do I go onto the internet. There is so much misinformation on the net that you need to know exactly what you’re looking for and be able to judge authenticity.

Your novel really left us wanting more and wondering what became of the Nus Nus and Alys. Will there be a sequel?

Maybe. They live on in my head! Their lives are not as easy as you might hope: unfortunately Charles II was to survive for only another couple of years, so Nus Nus’s life as a court musician will be shortlived…

Where/when will you set your next book?

I’m in the middle of writing the new novel which is a bit different to THE SULTAN’S WIFE. It’s set in the 12th century, amid the magnificent drama and appalling bloodshed of the Third Crusade, and at the moment is ironically entitled THE GLORY. It’s a big book, and not just about the war to regain Jerusalem from Saladin, and the terrible Siege of Acre (seen from within the walls), but also about a troupe of itinerant ‘miracle-makers’: medieval conmen who go from town to town faking miracles. As with all my work its central theme involves Christianity and Islam, how the two cultures clash and intersect; how atrocities are carried out in the name of religion, how we all manage tragically to misunderstand one another, and how that misunderstanding is manipulated by those in power.

I’m thoroughly enjoying writing something so different and so vast in scope. The research has been immense and I’ve been amazed how many times I have caught out recognized scholars in small errors just by the simple expedient of going back to the primary sources rather than relying on the Chinese whispers of popular history. It’s a lot of information to hold in your head, and sequencing the narrative between different viewpoint characters is a challenge. However, as George RR Martin’s editor, I’ve learned a lot about handling a big cast and using those different viewpoints to shift scene and time and offer the reader a sense of the epic as well as in-your-face, visceral experience. I’ve also recognised some of his source material for the big battles in the series (HBO’s second series of Game of Thrones is about to show us the Battle of the Blackwater: a masterclass in epic battle writing which George himself has scripted). I’m taking notes!

And of course there is romance even amid the horror: love springs up at the most unpromising of times and in the most unexpected places, like the toughest of wild flowers.