Marsilio Ficino: Liber de sole (1487), Chapter 4
In the heavens, definite spaces are noted in regard to the sun itself, within which the planets wander and regularly change their motions. . . Venus and Mercury wander a certain limited distance to and from the Sun. Venus is restricted to 49 degrees and Mercury to 28 degrees. . . The superior planets ascend as they approach the sun and descend as they go away from the sun. At conjunction with the Sun they are at the highest point of their epicycles, at opposition they are at the lowest point, and in quadrature they are at a mean altitude.
Nicolas Copernicus: De Revolutionibus (1543), I, 10.
Opinions differ as to Venus and Mercury which, unlike the others, do not altogether leave the sun. Some place them beyond the Sun, as Plato in his Timaeus; others nearer the Sun, as Ptolemy and many of the moderns . . . I think we must seriously consider the ingenious view held by Martianus Capella . . ., that Venus and Mercury do not go round the Earth like the other planets but run their courses with the Sun at the center, and so do not depart from him further than the size of their orbits is near the Sun …
We may extend this hypothesis to bring Saturn, Jupiter, and Mars into relation with this center, making their orbits great enough to contain those of Venus and Mercury and the Earth; and their proportional motions according to the Table demonstrate this. These outer planets are always nearer to the earth about the time of their evening rising, that is, when they are in opposition to the Sun, and the Earth between them and the Sun. They are more distant from the Earth at the time of their evening setting, when they are in conjunction with the Sun and the Sun between them and the Earth. These indications prove that their center pertains rather to the Sun than to the Earth, and that this is the same center as that to which the revolutions of Venus and Mercury are related.
Marsilio Ficino: Liber de Sole, Chapter 6
All locate the Sun, like a lord, in the center of the world, although for different reasons. The Chaldeans, for instance, [place it] in the middle of the planets, the Egyptians actually [place it] between two quintuple worlds, as surely the five planets are above it, and below it are the moon and the five elements. . . [Some] actually postulate the disposition of the Sun in this way, such that Saturn, Jupiter, and Mars are elevated above it, while on the other hand, Venus, Mercury, and the Moon are below the Sun, which proceeds as a king, taking the middle way. Going by other ways, weaker ones avoid him.
Nicolas Copernicus: De Revolutionibus, I, 10.
In the middle of all sits the Sun enthroned. In this most beautiful temple could we place this luminary in any better position from which he can illuminate the whole at once? He is rightly called the Lamp, the Mind, the Ruler of the Universe; Hermes Trismegistus names him the Visible God, Sophocles’ Electra calls him the All-seeing. So the Sun sits as upon a royal throne ruling his children the planets which circle round him.