What is the timeframe of the Gothic movement?

The Gothic movement was a metamorphosis of literature and art away from the optimistic toward the pessimistic view of life and society.  Castle of Otranto by Horace Walpole is widely considered to be the first true Gothic novel.  It was written in 1764 and spawned many early followers.  The Old English Baron (1778) by Clara Reeves and The Monk (1796) by MG Lewis helped to create the movement by mirroring the dark settings of Walpole's original work.

The Gothic movement continued well into the early 1800s but was on the decline by 1840, ending by 1850.  The movement inspired authors such as Poe, Dickens and Kipling, who turned toward the psychological thriller rather than pure gothic themes.