A letter written by Robert Grosseteste, the first chancellor of Oxford University and later Bishop of Lincoln from 1235 to 1253, illustrates the role that Neoplatonism played in the creative process of the architect in the Middle Ages. The letter was written from Oxford in around 1200, to Master Adam Rufus, a former student. According to Grosseteste, “It is said that the design is the model to which the craftsman looks to make his handiwork, in imitation of it and in its likeness.” Grosseteste’s letter exhibits a familiarity with the Enneads of Plotinus, which Grosseteste probably was not able to read directly but would have known through texts such as the Theology of Aristotle. In Enneads V.8.1, Plotinus compares two blocks of stone, one of which is carved into a statue by a craftsman, so that in which “the form is not in the material; it is in the designer before ever it enters into the stone…”, the forma artificii of Grosseteste.
Grosseteste uses the analogy of architecture: “So imagine in the artist’s mind the design of the work to be made, as in the mind of the architect the design and likeness of the house to be built; to this pattern and model he looks only that he may make the house in imitation of it.” The material of the building is organized in imitation of the idea in the mind of the architect; like the forms of nature in relation to the archetypes of the Platonic demiurge, the building is a shadow or reflection of the architectural idea. In the Enneads I.6.3, Plotinus asked, “On what principle does the architect, when he finds the house standing before him correspondent with his inner ideal of a house, pronounce it beautiful?”
In his cosmologies De Luce (or On Light, 1225–1228) and De lineis, angulis et figuris (or On lines, angles and figures, 1228–1233), written at Oxford, Robert Grosseteste would describe natural bodies as being formed by mathematical and geometrical entities created from light, as reflected from the lux spiritualis, the incorporeal, spiritual light; and in the Commentary on the Posterior Analytics (1228–1235) and the Hexaemeron (c. 1237), Grosseteste would describe the ascension of the soul from the material intellect to the agent intellect, in the apprehension of the divine intellect, intelligentia. These concepts show the influence of Plato and Plotinus and explain in part the intentions of the medieval architect.
Hendrix, John S., "Neoplatonism and English Gothic Architecture" (2013). School of Architecture, Art, and Historic Preservation Faculty Publications. 33.