‘There is no room for doubt that Astronomy was invented at the beginning of the World. As there is nothing more noteworthy than the regularity of movement among these great luminous bodies that turn unceasingly around the Earth, it is natural to think that one of the first interests of men was to consider their course and observe their periods. But mere curiosity alone was not solely responsible for leading men to set themselves astronomical speculations, for it can be maintained that necessity as well obliged them. For should one not observe the seasons that vary by the movement of the Sun, it would be impossible to make a success of agriculture; were one to fail to note the suitable times for travel, one could establish no Business; should one not have determined once and for all the length of the month and the year, there could be neither order established between civil affairs, nor could days be marked out for religious purposes: hence as agricultural farming, commerce, politics and even religion cannot do without astronomy, it is obvious that men must have been obliged to study this science right from the World’s beginning. Both sacred and secular history confirms this truth. What the Holy Scriptures reveals about the years that the ancient Patriarchs lived up to is proof positive that the first men studied the movements of the stars. For had they not taken account of the exact number of days that last in the varying phases of the Moon which serve to conceal the months; and of the number of months during which the Sun little by little approaches the Zenith and afterwards distances itself from it, marking the changes by increase and diminution of the days, which allow one to establish the length of the year, they could not have noted the number of years each Patriarch had lived, nor the times of their birth and death, as precisely as Moses records it in Genesis. And there certainly was need in this first age of the world to observe the stars with a great deal of care, for by the circuмstances of the history of the great flooding which are also reported in Genesis, one can see that the year from the time of the Deluge was regulated following the movements of the Sun and Moon: which supposes a boundless number of observations. It is yet to be understood how all the application imaginable by the first men studying the sky could have gained them so much knowledge of the movements of the stars, unless their lives were longer than ours. By the living of such long lives gained for them great advances in astronomy. Flavius Josephus (37-100AD) was of the opinion that so necessary was this science that one of the reasons why God granted the first men such a long-lasting life was to facilitate for them the knowledge of the movements of the stars.’--- J.D. Cassini, The Progress of Astronomy
‘While Tyco de Brahe was observing in Denmark, many famous astronomers gathered in Rome under the aegis of Pope Gregory XIII. They worked with great success at correcting the errors that had crept in insensibly in the [Julian] calendar by the precession of Equinoxes and through anticipation of new Moons. These errors later would have completely overturned the order established by the Councils for the celebrations of movable feasts had the calendar not been revised according to modern observations of the movements of the Sun and of the Moon compared with the old times. It was Aloysius Lilius (1510-1576) who invented the new form of the Gregorian year but after his death Christoph Clavius (1538–1612) perfected it, gave its explanation, and its defence.’--- J.D. Cassini, The Progress of Astronomy