Much medieval science was still dependent on the works of ancient Greeks such as Aristotle, in the natural sciences, and Galen, in medicine. However, the spread of education and the founding of universities at Oxford and Cambridge in the 12th and 13th centuries AD were signs of a new enthusiasm for knowledge. Roger Bacon (about 1214-92), a Franciscan friar, who studied at Oxford and Paris, wrote his Opus majus, or ‘great work’ in the 1260s. It is regarded as one of the foundations of modern science.

Bacon attacked authority and advocated experiment, attitudes which were at the heart of later modern science. Bacon was not just a theorist; he proved that air is necessary for combustion and predicted flight and submarine travel. This was at a time when inventions like clocks, gunpowder and spectacles were also reaching England from mainland Europe. Many advances in science from the 11th century onwards were the result of contacts with the Arab world. Arab scientists were already advanced in fields like medicine, mathematics and astronomy. Many of their texts were translated by scholars, but knowledge of their work grew from the contact made with the Muslim world during the crusades to Palestine. The practical applications of scientific instruments like astrolabes were soon recognised.