[whswhs]

According to Benedek Láng's Unlocked Books (which I consulted while working on the Worminghall supplement), medieval Catholic doctrine considered any magic that involved calling on spirits to be illicet, because it had an element of ritual that could be viewed as idolatrous or as "worshipping false gods." Most other forms of magic were or could be licit, though divination was problematic, other than oneiromancy, which had scriptural precedent.