Mathematician:John of Holywood

English mathematician and monk, also (perhaps better) known as Johannes de Sacrobosco (his name translated into Italian), best known for his works concerning astronomy and the calendar.

Proposed an amendment to the Julian calendar (at the time ten days adrift). His suggestions were influential on Christopher Clavius's own work to develop the Gregorian calendar.

Nationality
English

History

 * Born: c. 1195, (possibly) Halifax, Yorkshire, England
 * Died: c. 1256, Paris, France

Books and Papers

 * De Algorismo (concerning calculation using Arabic numbers)
 * 1220: Tractatus de Sphaera (the first astromomy text printed in 1472. A hugely influential work on astronomy, even though it had numerous errors.)
 * 1232: De Anni Ratione (discussing proposed corrections to the Julian calendar)
 * Tractatus de Quadrante (on the quadrant)