A dream vision or visio is a literary device in which a dream or vision is recounted as having revealed knowledge or a truth that is not available to the dreamer or visionary in a normal waking state. While dreams occur frequently throughout the history of literature, visionary literature as a genre began to flourish suddenly, and is especially characteristic in early medieval Europe. In both its ancient and medieval form, the dream vision is often felt to be of divine origin. The genre reemerged in the era of Romanticism, when dreams were regarded as creative gateways to imaginative possibilities beyond rational calculation.
This genre typically follows a structure whereby a narrator recounts his experience of falling asleep, dreaming, and waking, and the story is often an allegory. The dream, which forms the subject of the poem, is prompted by events in his waking life that are referred to early in the poem. The ‘vision’ addresses these waking concerns through the possibilities of the imaginative landscapes offered by the dream-state. In the course of the dream, the narrator, often with the aid of a guide, is offered perspectives that provide potential resolutions to his waking concerns. The poem concludes with the narrator waking, determined to record the dream – thus producing the poem. The dream-vision convention was widely used in European literature from late Latin times until the 15th century.