The Christian theories regarding the form and position of the whole world, the proofs of which are taken from Divine Scripture.

How long I put off the composition of my work regarding the figure of the world, even though other admirable men as well as thyself frequently urged me to undertake it, you know best of all, O dearest, God-loving and Christ-loving Pamphilus, a man worthy of that name, since all holy men love thee—a sojourner in the earthly Jerusalem, but enrolled among the first-born and the prophets, with whom when of yore I knew thee only by report I was knit in the bonds of warmest friendship; but now I have had the satisfaction of having seen thee face to face, when by the will of God you came hither to us, to Alexander's great city, and never ceased to importune us about this work, enfeebled though we were in body, afflicted with ophthalmia and costiveness of the bowels, and as the result suffering afterwards from constant attacks of illness; while besides we were deficient in the school-learning of the Pagans, without any knowledge of the rhetorical art, ignorant how to compose a discourse in a fluent and embellished style, and were besides occupied with the complicated affairs of everyday life.