A libertine is a person questioning and challenging most moral principles, such as responsibility or sexual restraints, and will often declare these traits as unnecessary or undesirable. A libertine 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.