H. R. Trevor-Roper, The European Witch-Craze of the Sixteenth and Seventeenth Centuries, NY: Harper and Row (1956 / 1969) pgs 115-116:

"...Before examining any heresy it is useful to ask who in fact articulated it. Was it the heretics themselves, or was it the inquisitors who articulated it for them?

It has been argued by some speculative writers that the demonology of the sixteenth century was, in essence, a real religious system, the old pre-Christian religion of rural Europe which the new Asiatic religion of Christ had driven underground but never wholly destroyed. But this is to confuse the scattered fragments of paganism with the grotesque system into which they are only long afterwards arranged. The primitive peoples of Europe, as of other continents, know of charms and sorcery, and the concept of night-riding... survived into the early Christian centuries; but the essential substance of the new demonology -- the pact with Satan, the witches' sabbat, the carnal intercourse with demons, etc., etc. -- and the hierarchical systematic structure of the kingdom of the Devil, are an independent product of the later Middle Ages...the Hammerers of Witches built up their systematic mythology of Satan's kingdom and Satan's accomplices out of the mental rubbish of peasant credulity and feminine hysteria..."

Trevor-Roper wrote at length about the tortures and trials inflicted on those accused of being a witch.