Nicolaus Copernicus — "The Earth also is not without a certain motion."

"And so, having obtained the opportunity, I now propose to explain the motions of the heavenly bodies, and the order of the universe, with greater certainty than has hitherto been possible."

"We are thus brought to a standstill by the realization that our previous theories were not only complicated but also inconsistent."

"For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study."

"For it is clear that the earth performs a double motion: one about its axis, and another about the sun."

"Therefore, since it is the heavens that contain all things, it is not the heavens that move, but rather the earth, which is contained within the heavens, that moves."