The Ghost of a Flea is a miniature painting by the English poet, painter and printmaker William Blake, held in the Tate Gallery, London. Measuring only 8.42 inches × 6.3 inches (21.4 × 16.2 cm), it is executed in a tempera mixture with gold, on a mahogany-type tropical hardwood panel. Completed between 1819 and 1820, it is part of a series of works depicting "Visionary Heads" commissioned by the watercolourist and astrologist John Varley (1788–1842).Fantastic, spiritual art was popular in Britain from around 1770 to 1830, and during this time Blake often worked on unearthly, supernatural panels to amuse and amaze his friends.
At 21.4 cm × 16.2 cm the work is a greatly reduced miniature portrait. Blake generally worked on a small scale; most of his illuminated pages, engravings and many of his paintings are only inches high. Although Ghost of a Flea is one of Blake's smallest works, it is monumental in its imagination. Its tiny scale achieves drama in contrasting the muscular bulk and apparent power of the creature against its incarnation in the panel as an insect.
Blake first met John Varley in the autumn of 1818. Varley was 30 years younger than the artist, and has been described as a "genial 17-stone bear of a man." A student of astrology and zodiacal physiognomy, Varley held a strong belief in the existence of spirits, but was frustrated by his inability to see them. Thus he was drawn to Blake, who claimed to have seen visions daily since when as a small child he had seen a tree "filled with angels, bright angelic wings bespangling every bough like stars." The two would often gather late at night in Varley's house, and played a game in which Varley would attempt to summon the spirit of a historical or mythological person. On the appearance of the spirit, Blake would then attempt to sketch their likeness.
According to Varley, the imagery of a Flea came to Blake during an 1819 séance. Varley described the scene:
"As I was anxious to make the most correct investigation in my power, of the truth of these visions, on hearing of this spiritual apparition of a Flea, I asked him if he could draw for me the resemblance of what he saw: he instantly said, 'I see him now before me.' I therefore gave him paper and a pencil with which he drew the portrait... I felt convinced by his mode of proceeding, that he had a real image before him, for he left off, and began on another part of the paper, to make a separate drawing of the mouth of the Flea, which the spirit having opened, he was prevented from proceeding with the first sketch, till he had closed it."