It had so happened that, in the course of his labours on behalf of the little stone figure and the girl with the ivy-leaves in her hair, Mr Honeyfoot had discovered something. He believed that he had identified the murderer as an Avebury man. So he had come to Wiltshire to look at some old documents in Avebury parish church. “For,” as he had explained to Mr Segundus, “if I discover who he was, then perhaps it may lead me to discover who was the girl and what dark impulse drove him to destroy her.” Mr Segundus had gone with his friend and had looked at all the documents and helped him unpick the old Latin. But, though Mr Segundus loved old documents (no one loved them more) and though he put great faith in what they could achieve, he secretly doubted that seven Latin words five centuries old could explain a man’s life. But Mr Honeyfoot was all optimism. Then it occurred to Mr Segundus that, as they were already in Wiltshire, they should take the opportunity to visit the Shadow House which stood in that county and which neither of them had ever seen.

Most of us remember hearing of the Shadow House in our schoolrooms. The name conjures up vague notions of magic and ruins yet few of us have any very clear recollection of why it is so important. The truth is that historians of magic still argue over its significance – and some will be quick to tell you that it is of no significance whatsoever. No great events in English magical history took place there; furthermore, of the two magicians who lived in the house, one was a charlatan and the other was a woman – neither attribute likely to recommend its possessor to the gentleman-magicians and gentleman-historians of recent years– and yet for two centuries the Shadow House has been known as one of the most magical places in England.

It was built in the sixteenth century by Gregory Absalom, court magician to King Henry VIII and to Queens Mary and Elizabeth. If we measure a magician’s success by how much magic he does, then Absalom was no magician at all, for his spells hardly ever took effect. However, if instead we examine the amount of money a magician makes and allow that to be our yardstick, then Absalom was certainly one of the greatest English magicians who ever lived, for he was born in poverty and died a very rich man.

One of his boldest achievements was to persuade the King of Denmark to pay a great handful of diamonds for a spell which, Absalom claimed, would turn the flesh of the King of Sweden into water. Naturally the spell did nothing of the sort, but with the money he got for half these jewels Absalom built the Shadow House. He furnished it with Turkey carpets and Venetian mirrors and glass and a hundred other beautiful things; and, when the house was completed, a curious thing happened – or may have happened – or did not happen at all. Some scholars believe – and others do not – that the magic which Absalom had pretended to do for his clients began to appear of its own accord in the house.