Satanism is a group of ideological and philosophical beliefs based on the character of Satan. Contemporary religious practice of Satanism began with the founding of the Church of Satan in 1966, although a few historical precedents exist. Prior to the public practice, Satanism existed primarily as an accusation by various Christian groups toward perceived ideological opponents, rather than a self-identity. Satanism, and the concept of Satan, has also been used by artists and entertainers for symbolic expression.
Accusations that various groups have been practicing Satanism have been made throughout much of Christian history. During the Middle Ages, the Inquisition attached to the Roman Catholic Church alleged that various heretical Christian sects and groups, such as the Knights Templar and the Cathars, performed secret Satanic rituals. In the subsequent Early Modern period, belief in a widespread Satanic conspiracy of witches resulted in mass trials of alleged witches across Europe and the North American colonies. Accusations that Satanic conspiracies were active and that they were behind events such as the French Revolution continued to be made in Christendom during the eighteenth to the twentieth century. In the 1980s and 1990s, the Satanic ritual abuse hysteria spread through the United States and United Kingdom, amid unfounded fears that groups of Satanists were regularly sexually abusing and murdering children in their rites. In virtually all of these cases, there is no corroborating evidence that any of those accused of Satanism were actually practitioners of a Satanic religion or guilty of the allegations levelled at them.
Since the 19th century, various small religious groups have emerged that self-identify as Satanists or use Satanic iconography. Satanist groups that appeared after the 1960s are widely diverse, but two major trends are theistic Satanism and atheistic Satanism. Theistic Satanists venerate Satan as a supernatural deity, viewing him not as omnipotent but rather as a patriarch. In contrast, atheistic Satanists regard Satan as merely a symbol of certain human traits.