scholars to study contemporary paganism from a historical perspective was the American Wiccan Aidan Kelly, who had been a founding member of the New Reformed Orthodox Order of the Golden Dawn and the Covenant of the Goddess during the 1970s. Having attained several academic qualifications, including in the field of religious studies, in the 1970s he began a study of the religious texts of Gardnerian Wicca, in order to establish a historical chronology for the tradition. The results of his study would only be published in 1991, as Crafting the Art of Magic. This would later be rewritten and republished in 2007 as Inventing Witchcraft. The prominent English historian Ronald Hutton of the University of Bristol later devoted the latter part of his book The Pagan Religions of the Ancient British Isles (1991) to an examination of the contemporary pagan religions that took these pre-Christian religions as a core influence. He followed this with several studies of British folk customs, but in 1999 returned to the field of Pagan studies when he published The Triumph of the Moon: A History of Modern Pagan Witchcraft, the first academic study of Wiccan history. Theoretical debates Pagan studies has been charged with failing to properly define "paganism", as some scholars use it solely to designate contemporary Paganism and others – like Michael York and Chas Clifton – using it to refer to a wide range of religious movements across the world and throughout history. A further problem arises from the fact that while Pagan studies scholars might adopt "paganism" in reference to pre-Christian belief systems in Europe, the term was increasingly rejected by archaeologists specialising in those belief systems. Pagan studies has failed to satisfactorily define "contemporary Paganism"; a minority of scholars have treated it as a singular religion within which groups like Wicca and Heathenry are denominations, while a larger group have instead treated it as a "group of comparative religions". The concern has been made that Pagan studies scholars would be "at a loss to convey (to ourselves and to others), what it is that we are actually studying. The current situation, in which widely differing definitions are being used in tandem, is clearly unsustainable." The religious studies scholar Markus Altena Davidsen published a critique of the field in 2012, via a review of the Handbook of Contemporary Paganism. He argued that Pagan studies was dominated by an essentialist and normative