De revolutionibus orbium coelestium Earth's axis rigidly to a Sun-centered sphere. The unfortunate consequence was that the terrestrial rotation axis then maintained the same inclination with respect to the Sun as the sphere turned, eliminating the seasons." To explain the seasons, he had to propose a third motion, "an annual contrary conical sweep of the terrestrial axis". It was not until the Great Comet of 1577, which moved as if there were no spheres to crash through, that the idea was challenged. In 1609, Kepler fixed Copernicus' theory by stating that the planets orbit the sun not in circles, but ellipses. Only after Kepler's
Paris in the 16th century the 16th century, Paris became first in Europe in book publishing. In 1530, Françis I created a new faculty at the University of Paris with the mission of teaching Hebrew, Greek and mathematics. It became the "Collège de France". In 1540, the Jesuit order established its first schools in Paris. In 1549, the first textbook of the French language, "Defense et illustration de la langue Française", by Joachim de Ballay, was published. Francis I died in 1547. His son, Henry II, made his official entrance into Paris in 1549 with a lavish procession and ceremony; the first Renaissance fountain in