"I hold the sun to be situated motionless in the center of the revolution of the celestial orbs while the earth revolves around the sun."

"The authority of a thousand is not worth the humble reasoning of a single individual who observes the facts."

"Eppur si muove! (And yet it moves!)"

"I am about to take leave of this earth, and I can say that I have seen more wonders than any man before me."

"The two books from which I draw my knowledge are the book of the created world and the book of the Holy Scripture."