PTHOLOME, PTHOLOMEE, THOLOME. Claudius Ptolemaeus (Ptolemy), fl. A.D. 139-161, invented the science of trigonometry and improved the method of fixing geographical positions by referring to their latitudes and longitudes. His most famous work, Mathematica syntaxis, or The System of Mathematics, a work in thirteen books written c. A.D. 151 and known as Almageste, a title derived from the Arabic name, al-Kitab-al-Midjisti (The Greatest Book), is a manual of the entire astronomy of the time, including the work of his predecessors, particularly Hipparchus, which has been lost. Ptolemy deals mainly with the stars, the sun, the moon, and the planets, and omits the comets, which he does not consider part of astronomy. He is also the first to portray the heavens as a geometrically conceived universe. Mathematica syntaxis was first translated from Greek into Arabic in 827, in the reign of the Abassid Caliph Ma'mum (813-833), but the translator is unknown. The first translator from Arabic into Latin was Gerard of Cremona, who completed the work at Toledo in 1175. An earlier translation from Greek into Latin was done in Sicily about 1160, also by an anonymous translator, but only Gerard's work passed into general circulation. Ptolemy's other works were also translated. The Latin rendering of Centiloquium, an abridgement of Quadripartitum (a short title meaning "The Four Books") done in 1136, is generally assigned to John of Seville. Plato of Tivoli translated Quadripartitum in 1138. Quadripartitum is the Latin translation of Tetrabiblos, "four books," the short title for Mathematical Treatise in Four Books. J.D. North suggests that the Tetrabiblos was Chaucer's principal source for astronomical and astrological information; the work was very well known and widely consulted during Chaucer's time.
Nicholas has Almageste among his books, MillT 3208. Dame Alys quotes two proverbs attributed to Ptolemy, WBP 181-182, 324-327; for these Karl Young cites a Latin Almagestum in a fourteenth-century manuscript, which Chaucer may have known. The proverbs are ascribed to Ptolemy in the preface to Gerard of Cremona's translation of 1175 (published in Venice in 1515). Ptolemy and Euclid are masters of dividing, SumT 2289. Lady Philosophy says that, according to Tholome, only a fourth part of the world is inhabited by living creatures, Bo II, Prosa 7.31-34. According to Ptolemy, the summer solstice or northern latitude of the sun is 23 degrees and 50 minutes in the head or beginning of Cancer, the tropic of summer, Astr I.17.8-10. Skeat (III: 354) points out that in Ptolemy's time the true value was 23 degrees 40 minutes, but in Chaucer's time it was 23 degrees 31 minutes. The references here are to Almagest I.13. [Gerard of Cremona: Nicholas1]
Ptholome, the ME variant of Latin (from Greek) Ptolemaeus, occurs once, in final rhyming position, WBP 324; Ptholomee, with long final vowel, appears twice in final rhyming position, WBP 182; SumT 2289; Tholome, a variant of Jean de Meun's Tholomee, occurs in Bo II, Prosa 7.34.