Among the most famous Franciscan friars from this time, Roger Bacon studied at Oxford, and later worked on optics and the refraction of light through lenses, leading to the development of spectacles. He had a reputation as unconventional, pursuing learning in alchemy and magic - interests which earned him the soubriquet 'Doctor Mirabilis'. This led to his rejection from the Order and eventual imprisonment. He died in Oxford not long after his release.
Roger Bacon was ahead of his time: he sought reform the calendar and, among many other projects, he discussed the possibility of early concepts of automobiles, aeroplanes and submarines. In 1266, many of these observations were published in his Opus Maius, only recognised centuries later for its brilliance and astonishing modernity.