A few years after he had returned from Italy, Copernicus wrote the first draft of his heliocentric theory in a small booklet called Commentariolus most probably written in Lidzbark Warmiński (Heilsberg) around 1509.
This manuscript was, de facto, a rough draft of De revolutionibus which was not yet ready for publication and is known today only from copies entitled Nicolai Copernici De hypotesibus motuum coelestium a se constitutus commentariolus. Copernicus made very few copies of Commentariolus available, and only to his closest associates and friends, namely, Marcin Biem of Olkusz (d. 1540), Mikołaj Prokopowicz of Szadek (1489–1564), Maciej Miechowita (1457–1523) and Bernard Wapowski (d. 1535).
In his foreword to Copernicus translation of Theophylact Simocattas Letters (1509), Laurentius Corvinus (d. 1527), a Silesian humanist, wrote about his friends interest in astronomy. The name of the Frombork astronomer was not unknown either to participants of the Fifth Lateran Council (1512–7) who, among other important issues, discussed the forthcoming reform of the Julian calendar and called on experienced mathematicians to assist them. Answering the summons of his spiritual fathers, Copernicus sent his proposal based on new and more accurate data to Rome before 4 June 1516. It is assumed that by this time the astronomer had already completed his first revision of De revolutionibus since the letter of dedication introducing the book includes his admission that this work has been hidden away not for a mere nine years but for nearly four times nine.
From Regional Public Library - Copernican Library in Toruń
By around 1525 Copernicus name was known in Poland, in the Holy See and in European academic circles. Nevertheless, he lingered over publishing his theory of the Earths orbit which, according to many theologians, contradicted the evidence given by the human senses and the letter of Holy Scripture. In 1533 Pope Clement V became intrigued by the heliocentric theory, while Nikolaus Schnberg (1472–1537), Cardinal of Capua, asked the astronomer to make his theory available to the academic world and send the findings to him. He was also willing to cover the cost of making a copy of the work and assured Copernicus that he was a great admirer of his talent.
Astronomers and theologians from Wittenberg and Nuremburg anxiously awaited the publication of the comprehensive work but, even though his closest friends Tiedemann Giese and Alexander Sculteti did their best to encourage him to promptly do so, Copernicus still hesitated to put his work into print.
It was not until Georg Joachim Rheticus (1514–74), a young mathematician from Wittenberg and a protégé of Philipp Melanchthon, arrived in Prussia in the spring of 1539 and visited the author that Copernicus changed his decision. Rheticus later wrote that, he had heard of the fame of Master Nicolaus Copernicus and that he regretted neither the financial expense nor the long journey and its hardships. On the contrary, it seemed to him that there was a great reward for these troubles, namely, that he, a rather daring young man, compelled Copernicus who must have feared serious critical attacks to share his ideas sooner with the whole world.
And so it happened that in May 1539 Rheticus arrived at Copernicus door. He was able to work out an agreement that he (Rheticus) would personally go to Gdańsk in 1540 and publish a summary of the main work in the form of a short treatise called Narratio prima and then go to Nuremburg and have De revolutionibus printed in Hans Petreiuss printing shop. Petreius was then one of the leading publishers, printing works by Martin Luther, Philipp Melanchthon, Erasmus of Rotterdam, Ulrich Zwingli, and even by King Henry VIII of England and unceasingly sought for new authors and was always ready to publish difficult academic texts often with complex illustrations. In his letters to the astronomer, Petreius persuaded Copernicus that he should entrust his printing shop with the task of publishing his manuscript, additionally assuring him that his workshop would be able to deliver published copies to any place in Europe.
Before the publication of De revolutionibus Copernicus corresponded with the Lutheran theologian Andreas Osiander from Nuremburg who suggested that he should declare his treatise a hypothesis only, which was to appease the peripatetics (followers of Aristotle) and theologians whose protests he feared most. Unshaken in his beliefs, Copernicus did not agree to this and, assisted by Rheticus, worked for months on his manuscript correcting and amending it where necessary. In the autumn of 1541 the work was ready for publication and the 400-page manuscript copy was taken to Nuremburg by Rheticus. Before the printing had been completed, Rheticus hastily left for Wittenberg, where, as a university professor, he gave lectures on the principles of his masters theory. In the spring of 1542 he published Copernicus De lateribus et angulis triangulorum (On the sides and angles of triangles), which was later included in De revolutionibus.
Rheticus was not able to hand the manuscript over to Petreius until as late as May 1542 and then only managed to oversee the printing for a few weeks. In May, nevertheless, the first two printed sheets of De revolutionibus were sent to Copernicus for proofreading. After he had read the comments of Andreas Osiander (a Nuremburg professor), Rheticus agreed with Petreius that from then on this doctor of theology and philosophy would supervise the publication process. However, he changed the title to De revolutionibus orbium coelestium, removed the original foreword written by Copernicus and replaced it with his own unsigned version in which he reduced the new representation of the world to a mere hypothesis. Unfortunately, Copernicus fell seriously ill at the beginning of December 1542 and was not able to correct this false representation. There is no information whether a copy of the book printed shortly before 21 March 1543 ever reached Warmia before the astronomers death.
Copernicus work, published in a small folio format, ran to 400–500 copies with 202 pages and, typographically, was very carefully prepared. The Latin text, divided into six books, was supplemented by elaborate geometric drawings and astronomic tables presenting results of the laborious research and calculations made by the astronomer himself which constituted the most solid arguments for the validity of his theory of the Universe.
The building of Petreiuss former printing shop at 9, Öberg Street, (located near Albrecht Drers birthplace) luckily survived the ravages of WWII.