Roger Bacon, born in 1214, and whose great scientific capacities were alluded to in the preceding chapter, was a man who stood alone in the thirteenth century on account of his linguistic skill and attainments in philosophy. The poor persecuted Franciscan was three centuries in advance of his age, but, despite all difficulties, he did much to promote a movement of mental independence which, soon after his death made itself rapidly manifest. The separation of philosophy from theology began to be perfected, and the destruction of scholasticism was thus secured. Roscelin, a canon of Compiègne, did not a little toward the attainment of this end, but much more was accomplished by an English pupil of Duns Scotus, at the commencement of the fourteenth century. He was named John Occam, born in the county of Surrey, and is often called simply Occam. He was a successful teacher at Paris, under Philip le Bel, at the epoch when the political powers strove to emancipate themselves from the ecclesiastical power. The monk sided with the sovereign, and wrote against the pretensions of pope Boniface VIII. Afterward he said to the emperor Louis of Bavaria, "Defend me with the sword, and I will defend you with the pen," and in like manner resisted pope John XXII. A man so bold in politics could not have been timid in philosophy, and his persevering courage procured him the name of Doctor invincibilis. The spirit of independence was everywhere aroused under the auspices of Occam, so that the old schools were quickened, and new masters were produced. Walter Burleigh flourished about 1337, and wrote commentaries on Aristotle, Porphyry, etc., while professor at Paris and Oxford. He was author of the first history of philosophy written in the middle age. Marsile of Inghen, founder of the university of Heidelberg, died in 1394. Thomas of Strasburg, author of a Commentary on The Master of Sentences, died in 1357. Thomas of Bradwardin, Archbishop of Canterbury, was not only a mathematician of uncommon power, but a great proficient in the more literary departments of high philosophy. He died in 1439.