The phrase "the burning times" was introduced in reference to the European and North American witch trials by Gerald Gardner in 1954 in his book Witchcraft Today.
Gardner claimed he had discovered an Old Religion based on an ancient tradition of witchcraft; the "burning times" were its period of greatest persecution, and a major reason for the secrecy maintained within the religion ever since.
His account relied heavily on the theories of Margaret Murray, now regarded as highly flawed; he also repeated Murray's figure of nine million victims. While Gardner referred to the witch hunts in general as "the burning times", he noted that burning was only practiced on the Continent and in Scotland; in England accused witches were hanged.
The burning times is nothing else that the founding myth of Gardner's new cult, loosely inspired from all European pagan practices.
The term The Burning Times was further popularised by Mary Daly in her 1978 book, Gyn/Ecology: The Meta-Ethics of Radical Feminism, who maintained that the trials were fundamentally a persecution of women by patriarchy; she expanded the term's meaning to include not only the witch-hunts but the "entire patriarchal rule".
Neo-Pagan author Starhawk subsequently introduced the term into her book The Spiral Dance in 1979. The term was adopted by various American feminist historians and popularised in the 1980s for all historical persecution of witches and pagans, again often quoting nine million casualties. They also referred to it as the "Women's Holocaust".