The central figure of that religion is the goddess Aradia, who came to Earth to teach the practice of witchcraft to peasants in order for them to oppose their feudal oppressors and the Roman Catholic Church.

Scholars are divided, with some dismissing Leland's assertion regarding the origins of the manuscript, and others arguing for its authenticity as a unique documentation of folk beliefs.

Along with increased scholarly attention, Aradia came to play a special role in the history of Gardnerian Wicca and its offshoots, being used as evidence that pagan witchcraft survivals existed in Europe, and because a passage from the book's first chapter was used as a part of the religion's liturgy.

After the increase in interest in the text, it became widely available through numerous reprints from a variety of publishers, including a 1999 critical edition with a new translation by Mario and Dina Pazzaglini.

According to folklorist Roma Lister, a contemporary and friend of Leland's, Maddalena's real name was Margherita, and she was a "witch" from Florence who claimed a family lineage from the Etruscans and knowledge of ancient rituals.

"[3] He received several hundred pages worth of material from her, which was incorporated into his books Etruscan Roman Remains in Popular Tradition, Legends of Florence Collected From the People, and eventually Aradia.

Major characters in the myths include the Roman goddess Diana, a sun god called Lucifer, the Biblical Cain as a lunar figure, and the messianic Aradia.

Leland summarises the mythic material in the book in its appendix, writing "Diana is Queen of the Witches; an associate of Herodias (Aradia) in her relations to sorcery; that she bore a child to her brother the Sun (here Lucifer); that as a moon-goddess she is in some relation to Cain, who dwells as prisoner in the moon, and that the witches of old were people oppressed by feudal lands, the former revenging themselves in every way, and holding orgies to Diana which the Church represented as being the worship of Satan".

Leland was struck by this cosmogony: "In all other Scriptures of all races, it is the male ... who creates the universe; in Witch Sorcery it is the female who is the primitive principle".

The themes in these additional chapters vary in some details from the first ten, and Leland included them partly to "[confirm] the fact that the worship of Diana existed for a long time contemporary with Christianity".

Leland explains its inclusion by a note that Diana, as portrayed in Aradia, is worshipped by outlaws, and Laverna was the Roman goddess of thievery.

[13] Pazzaglini concludes that Aradia represents material translated from dialect to basic Italian and then into English,[13] creating a summary of texts, some of which were mis-recorded.

[14] Leland himself called the text a "collection of ceremonies, 'cantrips,' incantations, and traditions"[4] and described it as an attempt to gather material, "valuable and curious remains of ancient Latin or Etruscan lore"[4] that he feared would be lost.

"[15] Leland wrote that "the witches even yet form a fragmentary secret society or sect, that they call it that of the Old Religion, and that there are in the Romagna entire villages in which the people are completely heathen".

[20] Mathiesen also dismisses the third option, arguing that while Leland's English drafts for the book were heavily edited and revised in the process of writing, the Italian sections, in contrast, were almost untouched except for corrections of "precisely the sort that a proofreader would make as he compared his copy to the original".

[23] Matthieseon concluded that Leland was working from an extant Italian-language original that he described as "authentic, but not representative" of any larger folk tradition.

[9] Anthropologist Sabina Magliocco examined the first option (that Leland's manuscript represented a folk tradition involving Diana and the Cult of Herodias), stated in her article "Who Was Aradia?

Magliocco wrote that the text "may represent a 19th-century version of [the legend of the Cult of Herodias] that incorporated later materials influenced by medieval diabolism: the presence of 'Lucifero,' the Christian devil; the practice of sorcery; the naked dances under the full moon.

Historian Ruth Martin states that it was a common practice for witches of Italy to be "naked with their hair loose around their shoulders" while reciting conjurations.

[36] Historian Franco Mormando refers to an Italian witch: "Lo and behold: in the first hours of sleep, this woman opens the door to her vegetable garden and comes out completely naked and her hair all undone, and she begins to do and say her various signs and conjurations ...".

[38] Valiente offers another explanation for the negative reaction of some neopagans; that the identification of Lucifer as the God of the witches in Aradia was "too strong meat" for Wiccans who were used to the gentler, romantic paganism of Gerald Gardner and were especially quick to reject any relationship between witchcraft and Satanism.

[40] The new translation of the book released in 1998 was introduced by Wiccan author Stewart Farrar, who affirms the importance of Aradia, writing that "Leland's gifted research into a 'dying' tradition has made a significant contribution to a living and growing one.

[44] The Norwegian classical composer Martin Romberg wrote a Mass for mixed choir in seven parts after a selection of poems from Leland's text.