He is said by Rous to have been made D.D. of Paris and to have been incorporated as D.D. at Oxford[1328]. When he returned to Oxford is unknown; probably soon after 1250. He must have lectured at this time; he won some fame, as he says himself[1329], but without doubt made many enemies. About the year 1257 or 1258--when Adam Marsh could no longer protect his great pupil--Roger was exiled from England and kept under strict supervision in Paris for ten years[1330]. In 1263 he wrote an astronomical treatise called _Computus Naturalium_[1331]. Soon after this, a clerk named Raymund of Laon mentioned Bacon’s name to the Cardinal Bishop of Sabina and roused the latter’s interest in his discoveries[1332]. Bacon sent a letter in reply to the Cardinal’s communication: this has not been preserved. In 1265 the Cardinal became Pope Clement IV. On 22nd of June 1266, Clement wrote requesting Roger to send him a fair copy of the work which Raymond had mentioned, setting forth the remedies he proposed, ‘_circa illa, quae nuper occasione tanti discriminis intimasti_;’ the friar was to do this, in spite of any constitution of his Order to the contrary, secretly and without delay[1333]. The Pope’s supposition that the work was already written was erroneous; ‘for,’ writes Roger[1334], ‘whilst I was in a different state of life, I had written nothing on science; nor in my present condition had I ever been required to do so by my superiors; nay, a strict prohibition has been passed to the contrary, under penalty of forfeiture of the book, and many days’ fasting on bread and water, if any book written by us (i.e. the Franciscans) should be communicated to strangers[1335].’ However, although the book was not yet written, and notwithstanding endless difficulties, want of money, want of mathematical and other instruments and tables, the restrictions of the Rule, jealousy of his superiors and brethren who, he says, ‘kept me on bread and water, suffering no one to have access to me, fearful lest my writings should be divulged to any other than the Pope and themselves[1336]’--