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] [Footnote 45: Philastrius: _De Hæresibus_, c. 133, (v. 12, p. 1264).] 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. [Footnote 46: Pseudo-Dionysius: _De Coelesti Ierarchia_, (v. 122, p. 10354).] [Footnote 47: Milman: VIII, p. 228-9. See the _Paradiso_.] [Footnote 48: Isidore of Seville: _De Ordine Creaturarum_, c. 5, sec. 3, (v. 83, p. 923).] [Footnote 49: Lombard: _Sententia_, Bk. II, Dist. I, sec. 8, (v. 192, p. 655).] [Footnote 50: Aquinas: _Summa Theologica_, pt. I, qu. 70, art. 2. (_Op. Om. Caietani_, V, 179).] 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.