On the Revolutions of the Heavenly Spheres

I have preferred to dedicate these night-studies of mine to Your Holiness rather than to anyone else, because even in this most remote corner of the earth where I live, you are held to be most eminent by the dignity of your order and by your love for all literature and even for mathematics, so that by your authority and judgment you can easily suppress the bites of those who slander, although there is a proverb that there is no remedy against the bite of a sycophant.

If perhaps there should be ματαιολόγοι empty talkers/babblers who, although they are ignorant of all mathematics, yet take upon themselves to judge them, because of some place in Scripture badly distorted for their purpose, or if they should presume to blame and attack this endeavor of mine, I do not concern myself with them, to the point that I even despise their judgment as rash. For it is not obscure that Lactantius, a writer otherwise famous but little of a mathematician, speaks quite childishly about the shape of the earth when he derides those who have declared that the earth has the form of a globe. Therefore, it should not seem strange to students if such people will laugh at us also. Mathematics is written for mathematicians, to whom these labors of mine will also seem, if my opinion does not deceive me, to contribute something to the ecclesiastical Republic, the leadership of which Your Holiness now holds. For not long ago, under Leo X, when the question of correcting the Ecclesiastical Calendar was being debated in the Lateran Council, it remained undecided for this reason alone, that the magnitudes of the years and months, and the motions of the Sun and Moon, were not yet sufficiently measured. Since that time, I have devoted myself to observing these more accurately, warned by that most distinguished man, D. Paul, Bishop of Fossombrone, who was then in charge of that business. What I have achieved in this matter, I leave to the judgment of Your Holiness especially, and of all other learned mathematicians. And so that I may not seem to promise more to Your Holiness about the utility of this work than I can provide, I now pass to the matter at hand.