Nicolaus Copernicus Albert, Alexander Jagiellon, and Sigismund I the Old. He was a friend and key advisor to each ruler, and his influence greatly strengthened the ties between Warmia and Poland proper. Watzenrode came to be considered the most powerful man in Warmia, and his wealth, connections and influence allowed him to secure Copernicus' education and career as a canon at Frombork Cathedral. Copernicus is postulated to have spoken Latin, German, and Polish with equal fluency; he also spoke Greek and Italian, and had some knowledge of Hebrew. The vast majority of Copernicus's extant writings are in Latin, the language of European
Nicolaus Copernicus Fracastoro, Gabriele Zerbi, Alessandro Benedetti—and read medical treatises that he acquired at this time, by Valescus de Taranta, Jan Mesue, Hugo Senensis, Jan Ketham, Arnold de Villa Nova, and Michele Savonarola, which would form the embryo of his later medical library. One of the subjects that Copernicus must have studied was astrology, since it was considered an important part of a medical education. However, unlike most other prominent Renaissance astronomers, he appears never to have practiced or expressed any interest in astrology. As at Bologna, Copernicus did not limit himself to his official studies. It was probably the Padua years