"Therefore, when I perceived that these and similar doubts arose concerning the order of the parts of the universe and the symmetry of its structure, I began to be vexed that no more definite explanati…"

"For it is the duty of an astronomer to gather by careful and skilled observation the history of the celestial movements, and then to investigate their causes or hypotheses about them, and then to pred…"

"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?"

"There are three kinds of motion of the earth, as I shall demonstrate below."

"The Sun, as if seated on a royal throne, governs the family of stars which wheel around it."