Formation of Copernicus's heliocentric theory

Timeline

1. 1507–1514Frombork · PolandCopernicus conducted long-term astronomical observations from an observatory he built at Frombork, reflecting on the complexity of Ptolemy's geocentric system and gradually forming a model with the sun at the center and planets orbiting it.
2. 1514–1520Polish and Central European scholarly circles · PolandCopernicus wrote the Commentariolus summarizing seven basic postulates of the heliocentric system, circulated in manuscript among a few astronomers and friends without public publication, yet already constituting a fundamental challenge to the geocentric worldview.