Decadent movement
Decadence generally refers to a "process, condition, or period of deterioration or decline, as in morals or art; decay" (http://www.thefreedictionary.com). The Decadent Movement was a transitory, yet considerable late 19th-century literary style. In the decadent movement writers of the time expressed tabu-topics like sexual orientation or sex in general in their works, which was an absolutely new approach to literature in the negative sense. Some writers of the Decadent Movement called themselves "Decadent" but the term "Decadent" arose in the literary world as a disparaging assessment from critics, criticising and making fun of the repective writers. The probably most famous British Decadents were Oscar Wilde and Aubrey Beardsley. Most Decadents were influenced by Gothic novels and by the works of Edgar Allen Poe and were associated with Symbolism or Aesthetism. Decadent literature contained fiction, poetry and novels, so it basically covered all three literary genres. The fact that Decadents rather belonged to the minority of people did not stop them from expressing their phantasies and inner desires in form of literature (and arts.) The Decadents favored art and artifice over the natural world, and in this respect were closely aligned to the Symbolist and Aesthetic movements of the same period. Decadence was not only present in Britain though. It also existed in Germany, France, USA and some other countries. In France, for instance Decadence was at least as influential on literature as it was in Britain. Famous French Decadents were, among others, Montesquieu and Charles Baudelaire.
Sources
http://www.thefreedictionary.com/decadence
http://libcom.org/library/decadence-aufheben-2
http://www.english.uwosh.edu/roth/Decadence.htm
http://r.wisegeek.com/what-was-the-decadent-movement-in-literature.htm