Another member of the Chartres group, William of Conches, was a disciple of Bernard of Chartres in his youth. He taught at Chartres probably as early as 1126. Between 1140 and 1150 he acted as tutor to the young Henry and Geoffrey Plantagenet.[393] Hauréau says that William believed that “la philosophie tient subordonnées à ses principes généraux, comme deux sciences subalternes, la théologie et la physique.”[394] His most significant book, the _De philosophia mundi_,[395] throughout exemplifies this attitude and reveals to us a mind deeply interested in physics and natural science for their own sakes and a desire to explain the phenomena of the universe according to natural and observable laws. The rationalism of his philosophy brought him into conflict with the ecclesiastical authorities and necessitated his retracting various opinions late in life.[396] He died either in 1150 or 1154. ALEXANDER NECKAM The scholars of the Chartres group formed the intellectual élite of their age. More in keeping with the normal habit of the period than their mode of thought was the manner in which the Englishman Alexander Neckam dealt with matters of natural science. Born in 1157, Neckam had become a professor at the University of Paris by 1180; later in life he returned to England, became abbot of Cirencester in 1213, and died in 1217.[397] His principal works were _De naturis rerum_, in prose, and a verse paraphrase and enlargement of it entitled _Laus sapiencie divine_, or _De laudibus divinae sapientiae_.[398] In these works we see that Neckam, though inspired by a lively curiosity and even by some degree of understanding of experimental and observational science, was on the whole less original and less courageous intellectually than either Theodoric of Chartres or William of Conches. Instead of trying to explain rationally the phenomena of nature as these earlier writers had done, he was nearly always content merely to describe these phenomena as facts and to draw lengthy moral lessons from them. * * * * *