ArgumentDuring the two decades before the turning point in Copernicus's personal and scientific development in 1510, he had experience of political activity which has been largely ignored by the existing Copernicus literature but part of which is reconstructed in outline in this paper. Given the close linkage between politics and astrology, Copernicus's likely reaction to astrology is re-examined here. This reconstruction also suggests that the turning point in 1510, when Copernicus left his post as secretary to his uncle Lucas Watzenrode (...) the prince-bishop of Warmia, was not only linked to Copernicus's first version of his heliocentric theory in theCommentariolus, but also to major political setbacks being experienced by Watzenrode during these years, and with the publication of Copernicus's translation of theLettersof Theophylactus Simocatta. Some of these considerations contribute to maintaining the view that Copernicus and his work were in several respects exceptional. (shrink)