The Philosophy of Natural Magic - Henry Cornelius Agrippa - Originally published in 1531-3, De occulta philosophia libri tres, (Three books of Occult Philosophy) proposed that magic existed, and it could be studied and used by devout Christians, as it was derived from God, not the Devil.
A revelatory account of the magus - the learned magician - and his place in the world of Renaissance EuropeAt the heart of the extraordinary ferment of the High Renaissance stood a distinctive, strange and beguiling figure: the magus.