Johannes de Sacrobosco or Sacro Bosco (John of Holywood, c. 1195 – c. 1256) was a scholar, monk, and astronomer (probably English, but possibly Irish or Scottish) who taught at the University of Paris and wrote the authoritative mediaeval astronomy text Tractatus de Sphaera.
Read more about Johannes De Sacrobosco: Origins, Life, Tractatus De Sphaera, Algorismus, On The Calendar, Works