The word decadence refers to a late 19th century movement emphasizing the need for sensationalism, egocentricity; bizarre, artificial, perverse, and exotic sensations and experiences. By extension, it may refer to a decline in art, literature, science, technology, and work ethics, or to self-indulgent behavior.
An orgy in Imperial Rome, by Henryk Siemiradzki
Romans during the Decadence, by Thomas Couture
Heliogabalus, High Priest of the Sun by Simeon Solomon (1866)
The Roses of Heliogabalus by Sir Lawrence Alma-Tadema (1888)
A libertine is a person devoid of most moral principles, a sense of responsibility, or sexual restraints, who sees these traits as unnecessary or undesirable, and is especially someone who ignores or even spurns accepted morals and forms of behaviour observed by the larger society. The values and practices of libertines are known collectively as libertinism or libertinage and are described as an extreme form of hedonism. Libertines put value on physical pleasures, meaning those experienced through the senses. As a philosophy, libertinism gained new-found adherents in the 17th, 18th, and 19th centuries, particularly in France and Great Britain. Notable among these were John Wilmot, 2nd Earl of Rochester, and the Marquis de Sade.
John Wilmot by Jacob Huysmans
Marquis de Sade by Charles-Amédée-Philippe van Loo