The gothic movement in literature started in England in 1764 with the publication of The Castle of Otranto
and flourished until 1820. Gothic fiction was the predecessor of modern horror fiction, but was more like a mystery that often involved the supernatural (ghosts, haunted buildings, hereditary curses); disturbing dreams or omens; and characters overcome with anger, sorrow, or terror. They were often set in dark castles or medieval ruins.
Gothic romance was by far the most prevalent form of the genre. Often times, these novels centered around a naive but dynamic young woman, like a governess or new bride, who finds herself in the company of a wealthy but intimidating older man with a mysterious past, and living in a gloomy mansion with peculiar servants or children.
Some of the most famous gothic novels include Mary Shelley's Frankenstein, Charlotte Brontë's Jane Eyre, and Daphne du Maurier's Rebecca.
Note that gothic literature can't be confined to its established time period. Poe's The Fall of the House of Usher, Henry James' The Turn of the Screw, and even Stephen King's work like The Shining and Delores Claiborne could fall under the classification of gothic fiction.