The Shadow House, located in the county of Wiltshire not very far from Avebury, was home to 16th-century magician Gregory Absalom, and later to his daughter, Maria Absalom. Absalom was arguably no magician at all, but he was a great salesman; in fact, he once persuaded 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..." 
Absalom used half of the diamonds to pay for the building of the Shadow House. It is known as one of the most magical buildings in England; in fact, many scholars believe that the magic which Absalom merely pretended to do began to appear in the house of its own accord. Certain well-attested stories (which may be read in Chapter 23 of our history) support this. Moreover, after Absalom's death his daughter Maria inherited the house and allowed it to become ruinous, in accordance with the belief that all ruined buildings belong to the Raven King; even broken dishes were left in pieces on the floor. She died sometime in the 18th century, apparently without heirs, and the Shadow House became ever more run-down and magical.
John Segundus and Mr Honeyfoot visited the House in 1809, over a century since the death of Maria Absalom, and there met Henry Woodhope and Jonathan Strange. It was this chance meeting that caused Strange to seek out Mr Norrell and offer his services as a pupil.