Though the authenticity and authorship of the received gospel of the witches studied and published US folklorist and journalist Charles Godfrey Leland in 1899 is disputed by later historians and ethnographers, what Leland through his intermediary and research assistant Donna Roma Lister—a widely respected British writer on the occult and accomplished medium in her own right, believed to be genuine religious text of a Tuscan coven has played an unimpeachably large role in informing and influencing contemporary Wiccan and Neopagan movements.
Syncretic and secret, the practise and spellcraft continued in parallel to the rituals of Roman Catholicism but hidden in plain sight as sort of a liberation doctrine to subvert and counter the oppression of the Church orthodoxy and social order. 
The titular messianic figure, similar to the Italian form of the name Herodias—the wife of Herod Antipas whose real genealogy was buried in the belief of early Christianity, a characterisation of course propagated by witches themselves, that for her complicity in the death of John the Baptist her spirit was condemned to wander the Earth forever and only permitted to rest in treetops between midnight and daybreak, whereas Erodiade was a continuation of the ancient Roman cult of Diana and her nymphs, a daughter sired by prideful angel Lucifer and sent by the goddess to be a teacher unto women and men who would break from the yoke of enslavement—see also—and the real proto-witch. The gospel in fragmented form was completed by Lister’s interviews and channelling to fill in the gaps. Much more, particularly on our collaborator and ghost-writer, from Public Domain Review contributor A D Manns at the link up top.