This has been a joy to write, and I hope that you’ve enjoyed reading it as much as I have loved working on it. The character of Luca Vero is entirely imaginary, as are Isolde and Freize. The character of Ishraq, though invented, is based on the many courageous and adventurous men and women who moved between the world of Christendom and the worlds of the other religions: Jews, Muslims, and even those farther afield.

What the book means to you, the reader, will be for you to decide. Most people will read it, I hope, for pleasure and with pleasure, and have the fun of joining young, passionate characters on a journey into an unknown world, where they face their fears and experience their powers. Some readers may want to know a little more about the world of the Order of Darkness.

The Order of Darkness is based on the fifteenth-century Order of the Dragon, which was created to defend Christendom against the apparently unstoppable rise of the Muslim Ottoman Empire. One of the characters who will arrive in the story in subsequent books, was introduced to this Order by his father when he was just a little boy and rose to become its commander, fighting at the very outpost of Christendom.

The investigation entrusted to Luca – to find the signs of the end of times – is a fictional version of the anxiety felt by most people after the fall of Constantinople. The rise of all sorts of strange phenomena in Europe at this time shows that many people were fearing that anything could happen – and was happening. Also, these were deeply superstitious times. People genuinely believed that there was another, unseen, world sometimes glimpsed but often bearing down upon their lives. For those of us who now live in a world where we try to measure and understand everything, it is hard to imagine what it would have been like to have no explanation for everyday events like illness, thunder, or an eclipse, yet having your world rocked by the death of a loved one, your house shaken by a thunderclap or your day turning into night as a dark moon eats up the sun.

Isolde is typical of the girls of her time in that her life would be completely determined by her father and, on his death, her brother or any male kinsman. Legally, she could not buy or sell land or property, and anything she inherited would automatically belong to her husband on marriage. She would have no rights of her own at all: a father or husband was legally allowed to beat her; he could care for her as well or as badly as he liked. In these sorts of circumstances life in a nunnery was probably preferable to a bad marriage – as Isolde decides. In the nunnery there was the possibility of a career (like the Lady Almoner, who joins as a little girl and rises in authority) and the chance to organise your own life inside the strict rules of the order. Many women relished the education, and many had a deep religious experience.

Poor boys had a similar chance at improving their lives if they were accepted into a monastery and someone like Luca – who has exceptional abilities – would have had a good chance of rising to be a clerk or secretary to a great lord, who would find his administrators in the ranks of the Church. If Luca had stayed inside the Church, he might have risen to become a senior cleric. Brother Peter is a career churchman like this; he came from a poor family but is rising up through the Church. Luca does not take this route because he uncovers the many frauds that were going on in medieval churches. People wanted to see miracles, and dishonest churchmen produced relics of saints that could not possibly be genuine, and faked mechanical toys like weeping statues. This was part of the superstitions of the times, but was promoted by the Church, which made its money from the payments of the faithful.

Freize is, at first sight, a more normal poor boy. He joins the monastery as a lay worker – not a priest but someone simply working in the monastery as he might have worked in a big house. He has a gift for handling animals, and for common sense. He would have been very poor in the medieval world. If he had not won a place in a monastery, he would probably have had to work in the fields and would have been regarded as the servant, almost the property, of the local lord, who ruled everything.

Ishraq is perhaps the most unusual character of the four. Brought into Europe from the Middle East by Lord Lucretili, she was raised as his daughter’s companion and protector, and he had her trained in fighting skills, medicine and other disciplines. She remains half in and half outside of the society as a heretic. Medieval Christians thought that anyone who did not accept the Bible just as they did was a non-believer and their soul was damned to hell. If someone chose to prosecute her for heresy, then she could be burned by the Church – but as long as she made no enemies she might pass through society with people showing little more than curiosity. There were probably far more heretics, Moors, Africans and other races and religions in Europe than have been counted.

If you are interested in the background history to the story, including some lovely medieval details on shoes, clothes, food, washing, courtship – almost everything! – you can visit my site orderofdarkness.com. Or you can do your own research; most of the things that I mention can be found in books or on the Internet, and also there is a pack of teachers’ notes available to share in the classroom, which can be downloaded from orderofdarkness.com or simonandschuster.co.uk.

I hope you enjoy the illustrations throughout the book. It’s not an author photo at the top of this note but a version of Christine de Pizan, a wonderful medieval woman, one of the first commercial writers in Europe. The endpapers inside the jacket are based on a section of a map of the world drawn by a monk from Venice, Fra Mauro, around 1450. The version at the front of the book is how he drew it, with the South at the top, which is how the Muslim map-makers showed the world. The version at the end of the book is printed upside-down so that you can see the countries shown more clearly, though the script is wrong reading. You can see a full version of the map on the Internet, or at orderofdarkness.com.

Why is this book different from my historical novels? Mostly my historical fictions are based on everything that we know about a real person, her life and her times. This novel is based on four purely fictional young people, and the world they live in. It reflects the historical reality of their times, but of course nobody but a fictional heroine has such an exciting day-to-day life! And why did I write it? Not because I have finished writing fictional biographies at all – there’s a new novel out this year, The Kingmaker’s Daughter – but I thought it would be fun to write something less rooted in the historical record. I wrote it for the pleasure that it has given to me and in the hope that you will like it too.

PHILIPPA GREGORY