A spell that causes a sense of false familiarity is used by Jonathan Strange in Venice, to gain access to the house of the elderly Hebrew gentleman sheltering Mrs Delgado. The effect of Strange's spell is to convince the servants of the house that they see him every day: hence they do not object when he enters[53].

A similar effect of false familiarity may be part of the complex enchantment cast by the gentleman with the thistle-down hair over Stephen Black. To give an example of its operation: on one occasion Toby Smith runs after Stephen to present him with a silver diadem that has mysteriously appeared in Mrs Brandy's shop. Smith is apparently under the impression it is some everyday object he has seen Stephen wear very often. He does not pause to ask himself whether butlers generally wear crowns[26]. Nor is Smith alone in this sort of delusion: others regularly fail to notice much that is odd in Stephen's life. Not a housemaid, for example, thinks to ask why Mr Black's bed-chamber should be so crammed with jewels, sumptuous princely robes, religious relics and inconveniently large works in marble by the Italian Masters[65]. It is a striking instance of the subtle artistry of the Gentleman's magic, that this should all be so.

But one should, perhaps, not be too surprised. The story of Alessandro Simonelli tells us much about the careless ease with which fairies delude the wits and senses of Christians.