Research Project


Astrology and Politics – The Case of Kepler and the Emperors Rudolph II, Matthias and Ferdinand II

Katrin Bauer

(PhD- Project)

At the beginning of the 17th century, astrology as political counsel was popular at many of the courts in Europe. The King of France, the Landgrave of Hassia, the Duke of Brunswick, and even the Pope, to name just a few examples, had Astrologers at their courts or were at least interested in obtaining astrological advice, but it was Rudolf II of Habsburg, Emperor of the Holy Roman Empire (1576-1612), who resided in Praha, who in particular had a primary interest in the sciences of the occult. Besides Alchemy, Necromancy, Magic, and other mantic practices, he was very fond of Astrology. At his court, first Tycho Brahe (1600-1601) and then Johannes Kepler (1601-1612) were appointed official Court Mathematicians, who were in charge of astrological analysis. These included the calculation of horoscopes as well as the interpretation of astrological configurations regarding the precise inquiries of the emperor. But how did Brahe and Kepler become Court Mathematicians? Was there some kind of network among the natural scientists of that period, which came into play? Who was connected with whom? And what was their personal interpretation of the role of a Court Mathematician?

My research covers the following aspects: starting with the astrological works of Kepler, first of all, their context must be described and clarified. Who ordered, for example, Birth-Charts and when were they delivered? Did the Astrologer, as may be the case with some horoscopes, produce calculations without being assigned to do so? What may he have expected? In the next step, the documents themselves will be consulted: do we find information about the self-interpretation of Kepler as a Court Mathematician? Or does he make any allusion to his scientific understanding? Subsequently, his potential connections to other scientists will be checked and classified.

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