The unmoved mover (Ancient Greek: ὃ οὐ κινούμενος κινεῖ, ho ou kinoúmenos kineî, "that which moves without being moved") or prime mover (Latin: primum movens) is a henotheistic concept advanced by Aristotle, a polytheist, as a primary cause or "mover" of all the motion in the universe. As is implicit in the name, the "unmoved mover" moves other things, but is not itself moved by any prior action. In Book 12 (Greek "Λ") of his Metaphysics, Aristotle describes the unmoved mover as being perfectly beautiful, indivisible, and contemplating only the perfect contemplation: itself contemplating. He equates this concept also with the Active Intellect. This Aristotelian concept had its roots in cosmological speculations of the earliest Greek "Pre-Socratic" philosophers and became highly influential