Two Principles: Darkness & Light
"From one root, therefore, arise the two principles of the world: Light and Darkness. From darkness, matter; from light, the form of the world was born—without which there is nothing in the world, and the world itself is nothing. Thus, two [principles] constitute all things in the world; and all things are one: for the two are nothing but one, from which, through which, and in which are all things. That, however, is outside and before all things, being the root of all.
From the One, therefore, comes Darkness, from which comes matter, which is the existence of the world, extending from the finite to the divine. From the same One also comes Light, which is the form and essence of the world. Thus, the world is subjected to both darkness and the errors of darkness, as well as to the clear truth and perception of light. It is subject to the passions of death, endowed with both evil and good, sometimes filling with the anguish and miseries of mortality, and at other times bringing joy and happiness to the same.
In this way, it is clear that God, or the Monad as the root, in both its properties—namely, contracting itself within itself and thereby assigning dominion to darkness, or expanding itself and thereby offering its goodness to the world and its creatures."
— Medicina Catholica, Seu Mysticvm Artis Medicandi Sacrarivm, c. 1629 by Roberto Fludd; Alias De Fluctibvs