Then the center of astronomical development shifted from Syria to Spain and mainly through this channel passed on into Western Europe. The scientific fame of Alphonse X of Castile (1252-1284 A.D.) called the Wise, rests chiefly upon his encouragement of astronomy. With his support the Alfonsine Tables were calculated. He is said[27] to have summoned fifty learned men from Toledo, Cordova and Paris to translate into Spanish the works of Ptolemy and other philosophers. Under his patronage the University of Salamanca developed rapidly to become within two hundred years one of the four great universities of Europe[28]—a center for students from all over Europe and the headquarters for new thought, where Columbus was sheltered,[29] and later the Copernican system was accepted and publicly taught at a time when Galileo's views were suppressed.[30]
Popular interest in astronomy was evidently aroused, for Sacrobosco (to give John Holywood[31] his better known Latin name) a Scotch professor at the Sorbonne in Paris in the 13th century, published a small treatise De Sphæri Mundo that was immensely popular for centuries,[32] though it was practically only an abstract of the Almagest. Whewell[33] tells of a French poem of the time of Edward I entitled Ymage du Monde, which gave the Ptolemaic view and was illustrated in the manuscript in the University of Cambridge with a picture of the spherical earth with men upright on it at every point, dropping balls down perforations in the earth to illustrate the tendency of all things toward the center. Of the same period (13th century) is an Arabian compilation in which there is a reference to another work, the book of Hammarmunah the Old, stating that "the earth turns upon itself in the form of a circle, and that some are on top, the others below ... and there are countries in which it is constantly day or in which at least the night continues only some instants."[34] Apparently, however, such advanced views were of no influence, and the Ptolemaic theory remained unshaken down to the close of the 15th century.
Aside from the adequacy of this explanation of the universe for the times, the attitude of the Church Fathers on the matter was to a large degree responsible for this acquiescence. Early in the first century A.D., Philo Judæus[35] emphasized the minor importance of visible objects compared with intellectual matters,—a foundation stone in the Church's theory of an homocentric universe. Clement of Alexandria (c. 150 A.D.) calls the heavens solid since what is solid is capable of being perceived by the senses.[36] Origen (c. 185-c. 254.) has recourse to the Holy Scriptures to support his notion that the sun, moon, and stars are living beings obeying God's commands.[37] Then Lactantius thunders against those who discuss the universe as comparable to people discussing "the character of a city they have never seen, and whose name only they know." "Such matters cannot be found out by inquiry."[38] The existence of the antipodes and the rotundity of the earth are "marvelous fictions," and philosophers are "defending one absurd opinion by another"[39] when in explanation why bodies would not fall off a spherical earth, they claim these are borne to the center.
How clearly even this brief review illustrates what Henry Osborn Taylor calls[40] the fundamental principles of patristic faith: that the will of God is the one cause of all things (voluntate Dei immobilis manet et stat in sæculum terra.[41] Ambrose: Hexæmeron.) and that this will is unsearchable. He further points out that Augustine's and Ambrose's sole interest in natural fact is as "confirmatory evidence of Scriptural truth." The great Augustine therefore denies the existence of antipodes since they could not be peopled by Adam's children.[42] He indifferently remarks elsewhere:[43] "What concern is it to me whether the heavens as a sphere enclose the earth in the middle of the world or overhang it on either side?" Augustine does, however, dispute the claims of astrologers accurately to foretell the future by the stars, since the fates of twins or those born at the same moment are so diverse.[44]
Philastrius (d. before 397 A.D.) dealing with various heresies, denounces those who do not believe the stars are fixed in the heavens as "participants in the vanity of pagans and the foolish opinions of philosophers," and refers to the widespread idea of the part the angels play in guiding and impelling the heavenly bodies in their courses.[45]
It would take a brave man to face such attitudes of scornful indifference on the one hand and denunciation on the other, in support of a theory the Church considered heretical.
Meanwhile the Church was developing the homocentric notion which would, of course, presuppose the central position in the universe for man's abiding place. In the pseudo-Dionysius[46] is an elaborately worked out hierarchy of the beings in the universe that became the accepted plan of later centuries, best known to modern times through Dante's blending of it with the Ptolemaic theory in the Divine Comedy.[47] Isidore of Seville taught that the universe was created to serve man's purposes,[48] and Peter Lombard (12th cent.) sums up the situation in the definite statement that man was placed at the center of the universe to be served by that universe and in turn himself to serve God.[49] Supported by the mighty Thomas Aquinas[50] this became a fundamental Church doctrine.
An adequate explanation of the universe existed. Aristotle, Augustine, and the other great authorities of the Middle Ages, all upheld the conception of a central earth encircled by the seven planetary spheres and by the all embracing starry firmament. In view of the phrases used in the Bible about the heavens, and in view of the formation of fundamental theological doctrines based on this supposition by the Church Fathers, is it surprising that any other than a geocentric theory seemed untenable, to be dismissed with a smile when not denounced as heretical? Small wonder is it, in the absence of the present day mechanical devices for the exact measurement of time and space as aids to observation, that the Ptolemaic, or geocentric, theory of the universe endured through centuries as it did, upheld by the authority both of the Church and, in essence at least, by the great philosophers whose works constituted the teachings of the schools.
CHAPTER II.
Copernicus and His Times.
DURING these centuries, one notable scholar at least stood forth in open hostility to the slavish devotion to Aristotle's writings and with hearty appreciation for the greater scientific accuracy of "infidel philosophers among the Arabians, Hebrews and Greeks."[51] In his Opus Tertium (1267), Roger Bacon also pointed out how inaccurate were the astronomical tables used by the Church, for in 1267, according to these tables "Christians will fast the whole week following the true Easter, and will eat flesh instead of fasting at Quadragesima for a week—which is absurd," and thus Christians are made foolish in the eyes of the heathen.[52] Even the rustic, he added, can observe the phases of the moon occurring a week ahead of the date set by the calendar.[53] Bacon's protests were unheeded, however, and the Church continued using the old tables which grew increasingly inaccurate with each year. Pope Sixtus IV sought to reform the calendar two centuries later with the aid of Regiomontanus, then the greatest astronomer in Europe (1475);[54] the Lateran Council appealed to Copernicus for help (1514), but little could be done, as Copernicus replied, till the sun's and the moon's positions had been observed far more precisely;[55] and the modern scientific calendar was not adopted until 1582 under Pope Gregory XIII.
What was the state of astronomy in the century of Copernicus's birth? Regiomontanus—to use Johann Müller's Latin name—his teacher Pürbach, and the great cardinal Nicolas of Cues were the leading astronomers of this fifteenth century. Pürbach[56] (1432-1462) died before he had fulfilled the promise of his youth, leaving his Epitome of Ptolemy's Almagest to be completed by his greater pupil. In his Theorica Planetarum (1460) Pürbach sought to explain the motions of the