Roger Bacon completes his work Opus Majus and sends it to Pope Clement IV, who had requested it be written; the work contains wide-ranging discussion of mathematics, optics, alchemy, astronomy, astrology, and other topics, and includes what some believe to be the first description of a magnifying glass. Bacon also completes Opus Minus, a summary of Opus Majus, later in the same year.
The leadership of Vienna forces Jews to wear Pileum cornutum,a cone-shaped head dress, in addition to the yellow badges Jews are already forced to wear.