"For a long time then, I reflected on this confusion in the astronomical
traditions concerning the derivation of the motions of the universe's
spheres. I began to be annoyed that the movements of the world machine,
created for our sake by the best and most systematic Artisan of all,
were not understood with greater certainty by the philosophers, who
otherwise examined so precisely the most insignificant trifles of
this world. For this reason I undertook the task of rereading the
works of all the philosophers which I could obtain to learn whether
anyone had ever proposed other motions of the universe's spheres than
those expounded by the teachers of astronomy in the schools. And
in fact I found in Cicero that Hicetas supposed the earth to move.
Later I also discovered in Plutarch that certain others were of this
opinion. ...Therefore, having obtained the opportunity from these
sources, I too began to consider the mobility of the earth."
-- Nicholas Copernicus,
-- Letter to Pope Paul III: Preface to De Revolutionibus, 1543
