“I want the painter, as far as he is able, to be learned in all the liberal arts, but I wish him above all to have a good knowledge of geometry….Our rudiments, from which the complete and perfect art of painting may be drawn, can easily be understood by a geometer, whereas I think that neither the rudiments nor any principles of painting can be understood by those who are ignorant of geometry. Therefore, I believe that painters should study the art of geometry.” Leon Battista Alberti, On Painting and on Sculpture in The Civilization of the Italian Renaissance: A Sourcebook. Ed. Kenneth Bartlett. 2nd Ed. (Toronto, 2011), p. 171. [Emphasis added]
It should not surprise us that Alberti thought artists should study geometry. Alberti was an architect and an artist. The study of geometry laid the foundation for the transformation of the artistic depiction of the world. However, notice that Alberti exhorted artists to study all the liberal arts. Therefore, he continued:
“Next, it will be of advantage if they take pleasure in poets and orators, for these have many ornaments in common with the painter. Literary men, who are full of information about many subjects, will be of great assistance in preparing the composition of a ‘historia,’ and the great virtue of this consists primarily in its invention. Indeed, invention is such that even by itself and without pictorial representation it can give pleasure.” Ibid.
Here Alberti compares the composition of a historical painting (historia) to the practice of literary and rhetorical invention. He understands the painting similarly to literary narrative presented by an orator. Invention is the process by which an orator asks questions to find commonplaces (loci) for his speech. For Alberti, a great work of art tells a compelling story to its observers.
Simply consider Michelangelo’s Sistine Chapel as an example. The great artist tells the story of God’s creation and restoration of the world and humanity. He finds his material in the commonplaces of the Bible.