In what year did Copernicus practice his profession?

childhood and education:
Nikolaus Kopernikus was born as Niklas Koppernigk on February 19, 1473 as the son of a wealthy Krakow copper merchant in the Hanseatic city of Thorn in what is now Poland. He grew up with his two sisters and one brother in a middle-class family. In addition to his work as a successful dealer, the father also worked as a lay judge, like his father before. He died when Nicolaus Copernicus was about ten years old. After the death of his mother, Lukas Watzenrode, Prince-Bishop of Warmia and his maternal uncle took care of him and his siblings and attached great importance to a good education and later high church positions for the two brothers Nikolaus and Andreas Kopernikus. Copernicus spent the first years of school at the Sankt-Johannes-Schule in his hometown, before he entered a higher school at the age of fifteen, although it has not yet been clear which educational institution it was. Conjectures suggest that Copernicus attended the monastery school of the brothers from living together in today's Chelmo until 1491 and received a theological education there. Copernicus then went to Cracow to study theology at the university like his brother for a few years. However, he did not complete his studies in Krakow, as he was much more interested in the natural sciences than in theology. At the request of his uncle, he went to Bologna, where he finally completed his studies in astronomy and Greek with a master's degree in 1500 and left the university as a humanist polymath.
After a year-long stay in Rome and a brief visit to Frauenburg in Warmia, he returned to Italy with his brother to study medicine and law at the University of Padua. He had received permission to do so from the cathedral chapter, where he would later work at the request of his uncle. In 1503 he received his doctorate in law in Ferrara and thus obtained the degree of Doctors iuris canonici. He needed this title in order to be able to take over the position offered to him.

Professional career and academic achievements:
After completing his academic training, Nicolaus Copernicus returned to his homeland and initially worked as a secretary for his uncle. He was also employed as his personal physician, although he had not completed his medical degree in Italy. Nevertheless, he soon settled in Frauenburg as a doctor and also took over a position in the cathedral chapter there, which Lukas Watzenrode had brought him. He continued his work as a doctor into old age. In his position in the cathedral chapter, however, Copernicus was busy administering the lands and government affairs of the diocese and was also instrumental in reforming the coinage system. Together with his uncle, Copernicus managed to maintain the region's political and economic independence from the Polish Empire. He was therefore repeatedly elected chancellor of the cathedral chapter from 1510 onwards. As a member of the Church, he was free in his professional position to lead a worldly life. Copernicus was little interested in questions of faith all his life and preferred to think about scientific, especially astromic, questions. His brother Andreas was also Canon of Warmia for some time, but fell ill with leprosy in 1508 and had to vacate his position. Presumptions suggest that he went to Italy and died there about ten years later.

In Bologna, Copernicus, who had been in close contact with many scholars there and had already been instructed in the use of astromic devices as an assistant to Domenicus Novara, dealt intensively with planetary orbits and astronomy. When he took up his position as canon after twelve years of studying abroad, he began to study astromic studies on a part-time basis. As early as 1514, he had gained the first important insights that led him to question the existing worldview. He countered the geocentric view of the world, which had been generally valid since ancient times, with the first considerations of circular movements of the celestial bodies around the sun. He observed the irregular orbits of the planets and concluded that the sun must be in the center of the cosmos. However, he discussed his first hypothesis of a heliocentric worldview exclusively with his closest confidants. Copernicus summarized the knowledge gained in a first manuscript, which was entitled "Commentariolus" and was not published. The writing was only rediscovered in 1877 and attributed to Copernicus. To this day it is not known when the work was written or who saw it during Copernicus ’lifetime. However, it is considered to be the direct forerunner of his main work "De revolutionibus orbium coelestium", which the astronomer only published in 1543. Three years earlier, his student Joachim Rhetikus had published the "Narratio Prima", in English "First Report", which made the main features of heliocentric teaching accessible to a broader public. Copernicus himself hesitated for a long time to publish the "Revolutionibus", although many of his friends from the church, including Nikolaus Cardinal von Schönberg and Tiedemann Giese, wanted to persuade him to do so. However, the astronomer himself was concerned that he would not be able to provide enough scientific evidence because he was lacking precise observations. His main work was only put to print a few months before his death on May 24, 1543. Copernicus himself is said to have touched the finished book before he died of a stroke in Frauenburg.

Private:
Little is known about the private life of Nicolaus Copernicus. As a canon in Frauenburg, despite his permission to lead a worldly life with all the luxury, marriage was forbidden. He is said to have had a temporary relationship with Anna Schillings, his housekeeper, but was forced by the church to end it. Accordingly, Copernicus remained childless.

Nicolaus Copernicus went down in history as one of the most important astromomes of modern times and has significantly shaped the modern worldview based on scientific facts. He spent a total of thirty years working out his theories, since he could never practice astronomy as a main occupation. The churchman, who had been a secular and busy church man throughout his professional life, reformed the Prussian coinage, was politically extremely clever and probably therefore shied away from publishing his pioneering scientific studies for so long. After all, his writings were later placed on the list of forbidden books by Rome and only in the course of the 18th century were recognized by the Church as the scientific facts that have formed the basis of modern astronomical research to this day.