Among the outstanding theologians of the twelfth century was Peter Abelard (1079–1142), whose tragic history is well remembered. In his _Expositio in hexaemeron_, _Sermones_, and more famous _Sic et non_ we find a few scattered observations of a geographical character. Though Abelard’s fame rests upon the keenness of his reasoning and the destructive brilliance of his dialectic, his position when dealing with the Works of the Six Days was that of mystic.[370] We shall have occasion to see how the geographical passages from his works reveal a love of elaborate allegory. _Hugh of St. Victor_ The monastic school of St. Victor in Paris was preëminently a center of twelfth-century mysticism.[371] A leading figure here was Hugh of St. Victor, who held the direction of studies after about the year 1125 and who enjoyed during his lifetime (he died in 1141) a great reputation for learning in things divine.[372] Among Hugh’s writings we find _Adnotationes elucidatoriae in Pentateuchon_, containing speculations on the Creation, and the curious treatises _De arca Noë mystica_, _De arca Noë morali_, and _De vanitate mundi_,[373] which display a love of symbolism and include the exposition of a strange theory of the westward course of the tide of civilization.[374] _Hildegard of Bingen_ Hildegard (1098–1179 or 1180), abbess of a Benedictine convent near Bingen on the Rhine, was another lover of the symbolic. Her mystic exaltation took the form of visions in which were revealed to her the secrets of the universe. With the knowledge thereby attained she served her fellow man as a prophetess and healer of disease. Besides a series of letters, she wrote three works recording her visions: _Scivias sive visionum ac revelationum libri tres_ (1141–1150), _Liber vitae meritorum_ (1158–1162), and _Liber divinorum operum simplicis hominis_ (1163–1170). She was also probably the author of two treatises, _Subtilitates diversarum naturarum creaturarum_ and _Causae et curae_, which, though not avowedly the record of visions, could hardly have been written except as the result of some form of religious experience.[375] Her “cosmology and physiology,” as Thorndike points out, were none the less in essential conformity with “the then prevalent theories of natural science” although she “displays no little originality in giving a new turn to the familiar concepts.” She does not, however, “evolve any really new principles of nature.”[376] _Peter Lombard and Peter Comestor_