[Perspectiva communis was written to] compress into concise summaries the teachings of perspective, which [in existing treatises] are presented with … - John Peckham

About John Peckham

John Peckham (or Pecham) (c. 1230 – 1292) was a native of Sussex who was educated at Lewes Priory and became a Franciscan friar about 1250. He studied under Bonaventure at the University of Paris and became regent master (official lecturer) in theology. He was a conservative theologian who debated Thomas Aquinas with some success. He also taught at Oxford University and then traveled to Rome via France, to study law. In Rome he received a papal appointment to the position of Lector Sacri Palatii (theological lecturer) in the papal palace schools, where his lectures were attended by large audiences, including many bishops and cardinals. After one or two years in Rome, he was appointed by Pope Nicholas III as Archbishop of Canterbury (1279–1292), where he became known as one of the three earliest champions of English clerical reform. Peckham's views on experimental science were guided by Robert Grosseteste and Roger Bacon. His work on optics, Perspectiva Communis, was a standard reference through the seventeenth-century. In it, he describes experiments and expounds upon a variety of topics including reflection, concave mirrors, eye anatomy and theories of vision, refraction and theories of the rainbow. He also produced works on mathematics and natural philosophy, to include discussions on astronomy, astrology and cosmology.