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 mention1 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 Messahala2 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 Astrolabe3 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
- 1The name of Ptolemy occurs once in The
Somnours Tale (D. 2289):
As wel as Euclide or (as) Ptholomee.
whiche declinacioun, aftur Ptholome, is 23 degrees and 50 minutes, as wel in Cancer as in Capricorne.
His Almageste and bokes grete and smale,
‘Who-so that nil be war by othere men,
By him shul othere men corrected be.
The same wordes wryteth Ptholomee;
Rede in his Almageste, and take it there.’
Of alle men y-blessed moot he be,
The wyse astrologien Dan Ptholome,
That seith this proverbe in his Almageste,
‘Of alle men his wisdom is the hyeste,
That rekketh never who hath the world in honde.’
- 2An Arabian scholar of the eighth century.
- 31.18 If, “This tretis, divided in fyve parties, wole I shewe thee under ful lighte rewles and naked wordes in English; for Latin ne canstow yit but smal, my lyte sone.”
- 4“And Lowis, yif so be that I shewe thee in my lighte English as trewe conclusiouns touching this matere, and naught only as trewe but as many and as subtil conclusiouns as ben shewed in Latin in any commune tretis of the Astrolabie, con me the more thank;” Prologue to the Astrolabe, 35—39.
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 Oxford5; and of the Arabian astronomer Abdilazi Alkabucius.6 In The Frankeleyns Tale Chaucer mentions the Tabulae Toletanae7 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 Rambeau8 who discusses the parallels between The Hous of Fame and the Divina Commedia.
- 5Skeat, Notes on the Astrolabe, Prologue, 62 “Warton says that ‘John Some and Nicholas Lynne’ were both Carmelite friars, and wrote calendars constructed for the meridian of Oxford. He adds that Nicholas Lynne is said to have made several voyages to the most northerly parts of the world, charts of which he presented to Edward III. These charts are, however, lost.”
- 6The Astrolabe, I. 8.9. According to Warton the work in question is an introduction to judicial astronomy. (Lounsbury, II. 398.)
- 7F. 1273. “His tables Toletanes forth he broght,”
- 8Englische Studien III 209. See also J. S. P. Tatlock. “Chaucer and Dante” in Modern Philology, III, 367. 1905.