The vast significance of this view, and its power in resisting any real astronomical science, we shall see, especially in the time of Galileo. The great triad of thinkers culminated in St. Thomas Aquinas--the sainted theologian, the glory of the mediaeval Church, the "Angelic Doctor," the most marvellous intellect between Aristotle and Newton; he to whom it was believed that an image of the Crucified had spoken words praising his writings. Large of mind, strong, acute, yet just--even more than just--to his opponents, he gave forth, in the latter half of the thirteenth century, his Cyclopaedia of Theology, the Summa Theologica. In this he carried the sacred theory of the universe to its full development. With great power and clearness he brought the whole vast system, material and spiritual, into its relations to God and man.(42) (42) For the beliefs of Chaldean astronomers in revolving spheres carrying sun, moon, and planets, in a solid firmament supporting the celestial waters, and in angels as giving motion to the planets, see Lenormant; also Lethaby, 13-21; also Schroeder, Jensen, Lukas, et al. For the contribution of the pseudo-Dionysius to mediaeval cosmology, see Dion. Areopagita, De Coelesti Hierarchia, vers. Joan. Scoti, in Migne, Patr. Lat., cxxii. For the contribution of Peter Lombard, see Pet. Lomb., Libr. Sent., II, i, 8,-IV, i, 6, 7, in Migne, tome 192. For the citations from St. Thomas Aquinas, see the Summa, ed. Migne, especially Pars I, Qu. 70, (tome i, pp. 1174-1184); also Quaestio 47, Art. iii. For good general statement, see Milman, Latin Christianity, iv, 191 et seq.; and for relation of Cosmas to these theologians of western Europe, see Milman, as above, viii, 228, note. Thus was the vast system developed by these three leaders of mediaeval thought; and now came the man who wrought it yet more deeply into European belief, the poet divinely inspired who made the system part of the world's LIFE. Pictured by Dante, the empyrean and the concentric heavens, paradise, purgatory, and hell, were seen of all men; the God Triune, seated on his throne upon the circle of the heavens, as real as the Pope seated in the chair of St. Peter; the seraphim, cherubim, and thrones, surrounding the Almighty, as real as the cardinals surrounding the Pope; the three great orders of angels in heaven, as real as the three great orders, bishops, priests, and deacons, on earth; and the whole system of spheres, each revolving within the one above it, and all moving about the earth, subject to the primum mobile, as real as the feudal system of western Europe, subject to the Emperor.(43)