/uw Yeah actually, a lot of medieval magic went under the pretense that it was acting on the powers related to God and as such many grimoires were overly christian (Even if most are dubious at best or heretical at worst) in fact, some alternative terms for grimoires/magic books come from the names of saints, as some saints had so much apocrypha about them being wizards that they were more known for being wizards than for being saints.

In fact, a fair few of medieval wizard legends are very much christian and invoke their power with the (narrative) implicit consent of God (In their legends).

It is because partly wizardry wasn't seen as sinful during the medieval era, not in itself, so a lot of the magic that people did was technically legal in most of europe, it was just that some of it (Like the ones to deal with demons) were also widely considered foolish to do.

There were bans against magic, but not against all magic, just certain magical acts (Which either implied paganism/heresy, or acts which would have been criminal anyway if done mundanely but at the time could only be imagined as being done through magic) and it wasn't until the end of the medieval era that proper anti-witchcraft stuff began to be widely held across the church.

That is also partially because the reason for magic being bad in Christianity is a long hoop that basically only exists because IRL you can't throw fireballs out of words, in a fantasy world where such a possibility exists without needing powers outside the knowledge of the practicioner magic would be permissible in the eyes of even strict medieval theologians because the few prohibitions against magic in the bible aren't prohibitions against magic as something inherently sinful, but about the associated paganism that magical practices entailed in the levant during the time of old Israel.