"It is impossible for the world machine to have this sensible earth, air, fire, or anything else for a fixed and immovable center. For in motion there is no simply minimum, such as a fixed center.... And although the world is not Infinite, it cannot be conceived of as finite, since it lacks boundaries within which it is enclosed. ... Therefore, just as the earth is not the center of the world, so the sphere of fixed stars is not its circumference."

"Since it always appears to every observer, whether on the earth, the sun, or another star, that one is, as if, at an immovable center of things and that all else is being moved, one will always select different poles in relation to oneself, whether one is on the sun, the earth, the moon, Mars, and so forth. Therefore, the world machine will have, one might say, its center everywhere and its circumference nowhere, for its circumference and center is God, who is everywhere and nowhere."
- Nicholas of Cusa (1401-64)

(Just a note, Nicholas was never accused of heresy for this view, but Giordano Bruno expanded on Nicholas' ideas and was burned at the stake for heresy against The Church in 1600.)