Some time before 1514 Copernicus made available to friends his “Commentariolus” (“Little Commentary”), a manuscript describing his ideas about the heliocentric hypothesis.[x] It contained seven basic assumptions (detailed below). Thereafter he continued gathering data for a more detailed work.
At about 1532 Copernicus had basically completed his work on the manuscript of Dē revolutionibus orbium coelestium; but despite urging by his closest friends, he resisted openly publishing his views, not wishing—as he confessed—to risk the scorn “to which he would expose himself on account of the novelty and incomprehensibility of his theses.”
In 1533, Johann Albrecht Widmannstetter delivered a series of lectures in Rome outlining Copernicus’s theory. Pope Clement VII and several Catholic cardinals heard the lectures and were interested in the theory. On 1 November 1536, Cardinal Nikolaus von Schönberg, Archbishop of Capua, wrote to Copernicus from Rome: