Both for Al-Farabi and Gundissalinus the sciences of images and judgments were undoubtedly astrological. Gundissalinus himself believes that the spiritual virtue of the celestial bodies is the efficient cause, ordained by the Creator, of generation, corruption, and other natural operations in this corporeal world. He defines _astrologia_ as we would astronomy, while he explains that _astronomia_ is the science of answering questions from the position of the planets and signs. There are many such sciences,--geomancy, hydromancy, aeromancy, pyromancy, chiromancy, and augury; but astronomy is superior to the rest because it predicts what will befall upon earth from the dispositions of the heavenly bodies. Gundissalinus also repeats Isidore’s distinction between _astronomia_ and _astrologia_, and between the natural and superstitious varieties of “astronomy.”[214] [Sidenote: Robert Kilwardby, _De ortu sive divisione scientiarum_.] At this point it may be well to note briefly a later work with a very similar title to that of Gundissalinus, namely, the _De ortu sive divisione scientiarum_ of Robert Kilwardby,[215] archbishop of Canterbury from 1272 to 1279. The work borrows a great deal from Isidore, Hugh of St. Victor, and Gundissalinus. One of its more original passages is that in which Kilwardby suggests an alteration in Hugh’s division of the mechanical arts, omitting theatrical performances as more suited to Gentiles than Catholics, and arranging the mechanical arts in a _trivium_ consisting of earth-culture, food-science, and medicine, and a _quadrivium_ made up of costuming, armor-making, architecture, and business-courses (_mercatura_), after the analogy of the seven liberal arts.[216] Kilwardby, as has been already noted elsewhere, repeats Hugh’s classification of the magic arts.[217] [Sidenote: Plato of Tivoli.]