Bacon, Roger, born near Ilchester in 1214, went to Oxford under the protection of Richard Grosseteste, Bishop of Lincoln, and by his ability won the favour of other great patrons. Completing his studies at Paris, he returned to Oxford, and entered the order of St Francis. He took up scientific pursuits with such ardour and success as to incur suspicions of dealing in magic. Pope Clement IV., who had been legate in England, heard of his fame, accepted a copy of his Opus Majus, and put a stop to his persecution, which was, however, renewed on the pope's death. Bacon passed ten years in prison, and was only released to die in 1294. His intellect, obscured by the superstitions of his day, was acute and far-reaching. He seems to have grasped every subject of speculative or scientific interest, and to have applied, intuitively, inductive methods to many branches of inquiry. In this way he often foreshadows modern discoveries. His practical achievements were great, but not destined to bear fruit for several generations. Gunpowder, the telescope, the air-pump, the diving-bell, and the camera obscura were conceived by his genius. The Gregorian Calendar, too, was one of his premature suggestions. Besides the Opus Majus, or Roots of Wisdom, he wrote about eighty treatises, some of which are included in the Thesaurus Chemicua; others have never been printed. Gunpowder is described in De Nullitate Magiae, and his Means of Avoiding the Infirmities of Old Age was translated by Browne in 1683.