Tragedy is a form of drama based on human suffering that invokes an accompanying catharsis or pleasure in audiences. While many cultures have developed forms that provoke this paradoxical response, the term tragedy often refers to a specific tradition of drama that has played a unique and important role historically in the self-definition of Western civilisation. That tradition has been multiple and discontinuous, yet the term has often been used to invoke a powerful effect of cultural identity and historical continuity—"the Greeks and the Elizabethans, in one cultural form; Hellenes and Christians, in a common activity," as Raymond Williams puts it.