A seminal work of Romanticism, Henry Fuseli's 1781 painting depicts a sleeping woman haunted by a grotesque incubus and a spectral horse.

Henry Fuseli, a Swiss-born painter active in London, completed The Nightmare in 1781. It remains one of the most recognisable images from the late eighteenth century. The composition depicts a woman in a deep, troubled sleep, her body draped across a bed with her head hanging over the edge. A small, grotesque creature, known as an incubus, squats upon her chest. This figure represents the physical manifestation of a nightmare, a concept that fascinated the artist and his contemporaries. To the left, a spectral horse with glowing eyes emerges from the shadows, its head peering through the heavy curtains. This inclusion draws upon folklore, specifically the association between horses and nocturnal visitations. Fuseli employs a dramatic use of chiaroscuro, with deep shadows contrasting against the pale, luminous form of the sleeping woman. The lighting directs the viewer's focus to the central figures, while the surrounding darkness creates a sense of claustrophobia and unease. Fuseli was deeply interested in the psychological aspects of human experience, particularly the irrational and the subconscious. By visualising the internal state of a dream, he moved away from the rationalism of the Enlightenment. The painting does not rely on classical mythology or historical narrative, but instead explores the subjective realm of fear and desire. The theatrical staging and the exaggerated posture of the woman contribute to the overall sense of drama. This work was first exhibited at the Royal Academy in 1782, where it caused a sensation among the public and critics alike. It continues to be studied for its early exploration of themes that would later occupy the field of psychoanalysis.