ents, he was a sickly child unable for years to attend school regularly. He finally left the monastary school in Mulifontane in 1586 and entered the university at Tübingen to stay for four and a half years. There he studied philosophy, mathematics, and theology (he was a Lutheran) receiving the degree of Master of Arts in 1591. While at the university he studied under Mæstlin, professor of mathematics and astronomy, and a believer in the Copernican theory. Because of Mæstlin's teaching Kepler developed into a confirmed and enthusiastic adherent to the new doctrine.
In 1594 he reluctantly abandoned his favorite study, philosophy, and accepted a professorship in mathematics at Grætz in Styria. Two years later he published his first work: Prodromus Dissertationum continens mysterium cosmographicum etc. (1596) in which he sought to prove that the Creator in arranging the universe had thought of the five regular bodies which can be inscribed in a sphere according to which He had regulated the order, the number and the proportions of the heavens and their movements.[1] The book is important not only because of its novelty, but because it gave the Copernican doctrine public explanation and defense.[2] Kepler himself valued it enough to reprint it with his Harmonia Mundi twenty-five years later, And it won for him appreciative letters from various scientists, notably from Tycho Brahe and Galileo.[3]
As Kepler, a Lutheran, was having difficulties in Grætz, a Catholic city, he finally accepted Tycho's urgent invitation to come to Prague.[4] He came early in 1600, and after some adjustments had been made between the two,[5] he and his family settled with Tycho that autumn to remain till the latter's death the following November. Kepler himself then held the office of imperial mathematician by appointment for many years thereafter.[6]
With the researches of Tycho's lifetime placed at his disposal, Kepler worked out two of his three great planetary laws from
