German scholar Heinrich Cornelius Agrippa

Heinrich Cornelius Agrippa (1486–1535) wrote his first and most famous work on magic in 1510. Entitled De occulta philosophia (Occult Philosophy), the book was based on a Christian Kabbalistic framework. 

English mathematician John Dee

John Dee (1527–1609), adviser to Queen Elizabeth I, combined the study of the natural sciences with magical evocations aimed at establishing contact with spirits from (what he called) the angelic realm. 

Italian friar Giordano Bruno

Italian philosopher, mathematician, and Dominican friar Giordano Bruno (1548–1600) was attracted to Neoplatonic and Hermetic ideas. In his 1584 work, De l’infinito, universo e mondi (On the Infinite Universe and Worlds), he proposed that the universe contained an infinite number of worlds and that these were all inhabited by intelligent beings.38 This idea flatly contradicted Church dogma, and Bruno paid the ultimate price for his heresy. 

Swiss physician Paracelsus

Philippus Aureolus Theophrastus Bombastus von Hohenheim (1493– 1541), who called himself Paracelsus because it took too long to say his whole name, was one of the first modern medical theorists, the founder of homeopathy, and a pioneer in wound surgery. Paracelsus stressed that exercise of the imagination was the beginning of all magical operations. 

For the youth of the early twenty-first century, Paracelsus is perhaps better known as a character on one of the collectible Chocolate Frog Cards in the Harry Potter novels.