Consequent to the importation into Italy of works purportedly by Hermes Trismegistus, some educated persons began to believe that astral influence might be brought down to earth via correspondences between earth and the heavens. Marsilio Ficino, employed by Cosimo de’Medici, wrote on the subject in De vita coelitus comparanda, which translates as “On capturing the life of the stars.” 
Marsilio Ficino treaded cautiously into the subject, but others were more bold. Not just an astral influence might be brought down. Edward Kelly and John Dee practiced Sciomancy (divination using ghosts or spirits), a form of Necromancy. 
Plotinus, author of the Enneads, wrote, in The Fourth Ennead, Third Tractate:
I think, therefore, that those ancient sages, who sought to secure the presence of divine beings by the erection of shrines and statues, showed insight into the nature of the All; they perceived that, though this Soul is everywhere tractable, its presence will be secured all the more readily when an appropriate receptacle is elaborated, a place especially capable of receiving some portion or phase of it, something reproducing it, or representing it, and serving like a mirror to catch an image of it.
Just as the divine intellect is reflected in the soul of the world (anima mundi), and from there reflected in material forms, star images, talismans, shrines and statues would be made as artificial (graven) images used as intermediaries. By manipulating such intermediaries, the ancient wise ones knew how to draw down part of the anima mundi into their vessels. 
But when the Egyptian priests could not persuade the people that there are gods, then they invented what turned out to be an evil magic which enticed discarnate entities into statues and made the statues themselves appear to be gods.  (Further background: What Happened To The Egyptians, Ersjdamoo’s Blog, May 12, 2015.)
This finally explains to me the big deal about the Second Commandment: Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. (Exodus 20: 4) This one is so important as to be #2, only second-place in importance to #1: Thou shalt have no other gods before me. (Exodus 20: 3) The prohibition against graven images was given to the children of Israel soon after they had escaped Egypt. And in Egypt, disaster had ensued after necromantic practices had animated statues and caused them to be worshipped as gods. Considering the then-recent context of Egyptian necromancy, it is no surprise that the children of Israel were given Commandments 1 and 2 as highest priority.
How could Giordano Bruno not have known what he was messing with? He had entered the Dominican order in 1563, so he surely must have been familiar with the Second Commandment. (Bruno later fled the Dominicans, in 1576.) Bruno made a wrong turn and actually came to believe the Egyptian religion had been superior to the Christian religion! Maybe it had been, once upon a time, but as shown in the previous blog entry, the Egyptians had been led astray when memory-knowledges cultivated by them were turned into magic by which they completely inverted the memory-knowledges of the representative church.
Dame Frances Yates describes the magic advocated by Giordano Bruno as “reactionary and barbaric.” Bruno “openly proclaims his Egyptianism as a religion; it is the good religion which was overwhelmed in darkness when the Christians destroyed it, forbade it by statutes, substituted worship of dead things, foolish rites, bad moral behaviour and constant wars…”  This is where Giordano Bruno went wrong: the problems with Christianity in his own time caused him to leap overboard in the opposite direction. This does not mean Bruno deserved to be burned at the stake, as he was in 1600! Being burned at the stake by Catholic Christians only underscores that yes, there were problems with Christianity in Bruno’s time.
The Renaissance return of Necromancy, a form of magic involving communication with the deceased, was partly responsible for an increase in the influence of evil spirits. When you summon the shade of your dear old Aunt Hattie, you are not always getting what you think: the earthbound spirits are of a low type, prone to dissimulation. The reinvigoration of still extant pagan practices brought about by the Renaissance revival caused a real “witchcraft” problem. The situation is complex, not so simple as portrayed in a good play but bad history, The Crucible, by Arthur Miller.
——- Sources ——-
 Giordano Bruno and the Hermetic Tradition, by Frances A. Yates. University of Chicago Press, 1991.
 Kelley, Edward (1555 – 1593), Occultopedia. http://www.occultopedia.com/k/kelley_edward.htm