on geography was allegedly originally ornamented with a map based on ancient and Arabic computations of longitude and latitude, but has since been lost. His (mistaken) arguments supporting the idea that dry land formed the larger proportion of the globe were apparently similar to those which later guided Columbus. In this work Bacon criticises his contemporaries Alexander of Hales and Albertus Magnus, who were held in high repute despite having only acquired their knowledge of Aristotle at second hand during their preaching careers. Albert was received at Paris as an authority equal to Aristotle, Avicenna and Averroes, a situation Bacon decried: "never in the world [had] such monstrosity occurred before." In Part I of the Opus Majus Bacon recognises some philosophers as the Sapientes, or gifted few, and saw their knowledge in philosophy and theology as superior to the vulgus philosophantium, or common herd of philosophers. He held Islamic thinkers between 1210 and 1265 in especially high regard calling them "both philosophers and sacred writers" and defended the integration of Islamic philosophy into Christian learning. Calendrical reform In Part IV of the , Bacon proposed a calendrical reform similar to the later system introduced in 1582 under Pope Gregory XIII. Drawing on ancient Greek and medieval Islamic astronomy recently introduced to western Europe via Spain, Bacon continued the work of Robert Grosseteste and criticised the then-current Julian calendar as "intolerable, horrible, and laughable". It had become apparent that Eudoxus and Sosigenes's assumption of a year of 365¼ days was, over the course of centuries, too inexact. Bacon charged that this meant the computation of Easter had shifted forward by 9 days since the First Council of Nicaea in 325. His proposal to drop one day every 125 years and to cease the observance of fixed equinoxes and solstices was not acted upon following the death of Pope Clement IV in 1268. The eventual Gregorian calendar drops one day from the first three centuries in each set of 400 years. Optics In Part V of the , Bacon discusses physiology of eyesight and the anatomy of the eye and the brain, considering light, distance, position, and size, direct and reflected vision, refraction, mirrors, and lenses. His treatment was primarily oriented by the Latin translation of Alhazen's Book of Optics. He also draws heavily on Eugene of Palermo's Latin translation of the Arabic translation of Ptolemy's Optics; on Robert Grosseteste's work based