Today in some calendars is the memorial of St. Anicius Manlius Severinus Boethius, best known for his Consolation of Philosophy. From his little treatise, "The Trinity Is One God, Not Three Gods":
Theology does not deal with motion and is abstract and separable, for the Divine Substance is without either matter or motion. In Physics, then, we are bound to use scientific, in Mathematics, systematical, in Theology, intellectual concepts; and in Theology we will not let ourselves be diverted to play with imaginations but will simply apprehend that Form which is pure form and no image, which is very being and the source of Being. For everything owes its being to Form. Thus a statue is not a statue on account of the brass which is its matter, but on account of the form whereby the likeness of a living thing is impressed upon it: the brass itself is not brass because of the earth which is its matter, but because of its form. Likewise earth is not earth by reason of unqualified matter,11 but by reason of dryness and weight, which are forms. So nothing is said to be because it has matter, but because it has a distinctive form. But the Divine Substance is Form without matter, and is therefore One, and is its own essence. But other things are not simply their own essences, for each thing has its being from the things of which it is composed, that is, from its parts.