Spain. For several centuries Aristotle represented in the eyes of most scholastics “the last possibility of wisdom and learning.” But by the middle of the thirteenth century Ptolemy began to be rediscovered. The Ptolemaic system of planetary motions was briefly described in a handbook compiled by John Halifax of Holywood, better known as Sacrobosco. Roger Bacon wrote on the spheres, the use of the astrolabe, and astrology, following Ptolemy in his general ideas about the universe. The great mediaeval scholar and philosopher, Thomas Aquinas, was also familiar with the Ptolemaic system; but to most of the men of the thirteenth century Ptolemy’s works remained quite unknown. The real revival of Greek astronomy took place in the fourteenth century when scholars began to realize that new work in astronomy must be preceded by a thorough knowledge of the astronomy of the Alexandrian school as exhibited in the Syntaxis of Ptolemy. It was then that Greek and Latin manuscripts of works on astronomy began to be eagerly sought for and deciphered, and a firm foundation constructed for the revival of theoretical astronomy.

II

Chaucer’s Scientific Knowledge

It was in the fourteenth century that Chaucer lived and wrote, and his interest in astronomical lore is, therefore, not surprising. Although the theories of astronomy current in Chaucer’s century have been made untenable by the De Revolutionibus Orbium of Copernicus, and by Kepler’s discovery of the laws of planetary motion; although the inaccurate and unsatisfactory methods of astronomical investigation then in use have been supplanted by the better methods made possible through Galileo’s invention of the telescope and through the modern use of spectrum analysis; yet, of all scientific subjects, the astronomy of that period could most nearly lay claim to the name of science according to the present acceptation of the term. For, as we have seen, the interest in astrology during the Middle Ages had fostered the study of observational astronomy, and this in turn had furnished the science a basis of fact and observation far surpassing in detail and accuracy that of any other subject.

Practically all of Chaucer’s writings contain some reference to the movements and relative positions of the heavenly bodies, and to their influence on human and mundane affairs, and in some of his works, especially the treatise on The Astrolabe, a very technical and detailed knowledge of astronomical and astrological lore is displayed. There is every reason to suppose that, so far as it satisfied his purposes, Chaucer had made himself familiar with the whole literature of astronomical science. His familiarity with Ptolemaic astronomy is shown in his writings both by specific mention[1] of the name of Ptolemy and his Syntaxis, commonly known as the ‘Almagest,’ and by many more general astronomical references.

Even more convincing evidence of Chaucer’s knowledge of the scientific literature of his time is given in his Treatise on the Astrolabe. According to Skeat, Part I and at least two-thirds of Part II are taken, with some expansion and alteration, from a work on the Astrolabe by Messahala[2], called, in the Latin translation which Chaucer used, “Compositio et Operatio Astrolabie.” This work may have been ultimately derived from a Sanskrit copy, but from Chaucer’s own words in the Prologue to the Astrolabe[3] it is clear that he made use of the Latin work. The rest of Part II may have been derived from some general compendium of astronomical and astrological knowledge, or from some other of the treatises on the Astrolabe which Chaucer says were common in his time.[4]

Other sources mentioned by Chaucer in The Astrolabe are the calendars of John Some and Nicholas Lynne, Carmelite friars who wrote calendars constructed for the meridian of Oxford[5]; and of the Arabian astronomer Abdilazi Alkabucius.[6] In The Frankeleyns Tale Chaucer mentions the Tabulae Toletanae,[7] a set of tables composed by order of Alphonso X, king of Castile, and so called because they were adapted to the city of Toledo. Works which served Chaucer not as sources of information on scientific subjects but as models for the treatment of astronomical lore in literature were the De Consolatione Philosophiae of Boethius, which Chaucer translated and often made use of in his poetry; and the works of Dante, whose influence on Chaucer, probably considerable, has been pointed out by several writers, notably Rambeau[8] who discusses the parallels between The Hous of Fame and the Divina Commedia.

III

Chaucer’s Cosmology

Chaucer wrote no poetical work having a cosmographical background as completely set forth as is that in Dante’s Divine Comedy or that in Milton’s Paradise Lost. Although his cosmological references are often incidental they are not introduced in a pedantic manner. Whenever they are not parts of interpolations from other writers his use of them is due to their intimate relation to the life his poetry portrays or to his appreciation of their poetic value. When Chaucer says, for example, that the sun has grown old and shines in Capricorn with a paler light than is his wont, he is not using a merely conventional device for showing that winter has come, but is expressing this fact in truly poetic manner and in words quite comprehensible to the men of his day, who were accustomed to think of time relations in terms of heavenly phenomena.

Popular and scientific views of the universe in Chaucer’s century were by no means the same. The untaught man doubtless still thought of the earth as being flat, as it appears to be, as bounded by the waters of the ocean, and as covered by a dome-like material firmament through which the waters above sometimes came as rain; while, as we have seen, by the fourteenth century among scholars the geocentric system of astronomy was firmly established and the spheres and epicycles of Ptolemy were becoming more widely known. It is the view held by the educated men of his century that Chaucer’s poetry chiefly reflects.

1. The Celestial