Fuseli had originally intended to become a theologian. In Zurich he studied under the philosopher Johann Jakob Bodmer, who introduced him to Shakespeare, Dante, Homer, Milton and the Nibelungenlied, a medieval epic that German readers of the time regarded as their own equivalent of Homer^[1]. His close friendship with the poet and physiognomist Johann Kaspar Lavater, an opponent of strict rationalism despite his own scientific interest in how facial features expressed character, put Fuseli in direct contact with the German literary movement Sturm und Drang and its fascination with intense feeling over cool reason^[1]. After moving to London in 1764, he was encouraged by Joshua Reynolds to take up painting as a career, and travelled to Rome in 1770, where he spent close to eight years absorbing the influence of Michelangelo's Sistine Chapel ceiling and Mannerist painters such as Parmigianino and Rosso Fiorentino, a taste that set him apart from painters still devoted to calmer classical models^[1][2]. While in Rome he also knew the painter Anton Raphael Mengs and became friendly with Jacques-Louis David, and it was Fuseli who later helped introduce David's severe, linear style of drawing to British artists, even though his own manner developed in an entirely different, more turbulent direction^[2].

Fuseli's reputation rests above all on The Nightmare, shown at the Royal Academy in 1781, in which a sleeping woman lies draped across a bed with a squatting demon on her chest and a wild-eyed horse bursting through the curtains behind her^[3]. The picture's mixture of horror and unmistakable eroticism unsettled contemporaries: Horace Walpole, on seeing a later Fuseli picture at the Royal Academy, called it 'shockingly mad, madder than ever, quite mad'^[3]. The Nightmare's influence long outlasted its own moment; a reproduction of the painting reportedly hung for years in Sigmund Freud's consulting room, a measure of how directly it seemed to anticipate later ideas about the unconscious mind^[3].

Where many of his academic contemporaries drew their subjects from Roman history or classical mythology, Fuseli turned instead to Homer, Shakespeare, Milton, Spenser and the invented Gaelic epic Ossian, choosing scenes of psychological and physical extremity over noble, virtuous set pieces^[1]. His treatment of Shakespeare's A Midsummer Night's Dream, showing Titania enthroned over the transformed weaver Bottom, turned a comic episode into a dream vision crowded with beguiling and grotesque figures rather than a straightforward illustration of the text^[4]. This same appetite for literary and legendary source material, treated as a vehicle for the fantastic rather than for moral instruction, runs through Fuseli's chivalric and Northern subjects more broadly, of which this depiction of Percival delivering Belisane from enchantment is one example.