When they were introduced in 1818, the astronomer and artist John Varley was struck by Blake’s visionary capacity. As a mutual friend put it, Varley ‘readily devoured all the marvellous in Blakes most extravagent utterances’ [sic]. Varley encouraged Blake to draw the figures that appeared to him, resulting in a series of so-called ‘visionary heads’. This unusual example was then used by Varley as an illustration of ‘Gemini’ in his Zodiacal Physiognomy (see the reproduction on the plinth by this showcase). Blake later developed the sketch to produce a finished tempera, hanging nearby.