We must first discuss what was known and believed about the earth in its larger relations, both in time and space, to the remainder of the universe: opinions about the Creation, about the size and shape of our terrestrial globe, about the influences exerted by the heavenly bodies in determining or affecting geographical conditions upon its surface. In the Introduction we explained why it is justifiable when dealing with ancient and medieval geography to wander into the fields of cosmogony and cosmography far beyond what are now regarded as the rightful limits of geography. The present chapter, it is hoped, will make clear how closely medieval conceptions of the present condition of the earth may be connected with the medieval idea of the origins and nature of the universe. _GENERAL CHARACTER OF THE COSMOLOGY AND NATURAL SCIENCE OF THE PERIOD_ These difficult questions of cosmogony, cosmology, and cosmography excited keen and vivid thinking because they lie on the border between philosophy and theology. Men were more interested in attempting to solve the insoluble mysteries of God and the universe than they were in the world of nature immediately surrounding them. Immense and weighty volumes were written in commentary on the Works of the Six Days, wherein complicated arguments were elaborated with the finesse of scholastic logic. In an age of faith, the religious enthusiasm of the architect and artisan was transmuted into lofty cathedrals; that of the theologian turned to the elucidation of the words of Scripture. To analyze these words, to comment upon their minutest detail, to reveal the meaning that presumably lay behind them was not only a work of piety and devotion but an absorbing intellectual pastime for keen-witted thinkers. In more concrete realms of natural science, the epoch was characterized by little enough observation and creative thought. The teachings of Plato, of Aristotle, and of the other available classical, Arabic, and early Christian authorities were accepted and adopted uncritically. Very different was the case with matters of cosmogony and cosmography. Here was highly controversial ground where classical opinions were either enthusiastically defended as casting light on Scripture or else bitterly attacked as subversive of all truth. THE CHARTRES GROUP: BERNARD SYLVESTER AND THEODORIC