(b. London, England, ca. 1343–1344; d. London, 25 October 1400),
His father, John, and his grandfather and step-grandfather were vintners and wine merchants with some wealth and standing at court and some experience in public office. For his mother, probably Agnes de Copton, this was the second of three marriages. The earliest records of Geoffrey Chaucer show him in 1357 in the household, probably as a page, of Elizabeth, countess of Ulster, and her husband, Prince Lionel. Thereafter he was with the English army in France.
He was married by 1366 to Philippa Roet, sister of a wife of John of Gaunt. After holding many public offices, Chaucer became controller of customs for wools and hides in the port of London, then clerk of the king’s works; he held several other high offices and sinecures. In 1399 he leased for fifty-three years a house in the garden of Westminster Abbey, but died there the next year.
Chaucer’s popular masterpiece, the Canterbury Tales, is of cours the chief reason for his fame, so much so that his translation of Boethius’ De consolatione philosophiae and his other books are often forgotten. In particular, his two astronomical works, A Treatise on the Astrolabe (1391) and Equatorie of the Planet is (1392), both present considerable problems. They are both securely dated to his later years, after the bulk of the poetry, and they are remarkable as being quite self-consciously written in the vernacular instead of the usual Latin of such scholarship. Both books are clearly pedagogic in intent, and both display clear technical mastery of the special line of instrumentation associated at this time principally with Merton College, Oxford, which had specialized in instruments and in Alfonsine astronomy for two generations before. The Astrolabe, modeled on a treatise by Messahalla, describes the construction and use of this popular instrument for computing the position of any bright star as seen from any particular place at any time of any day of the year. It is an analogue method of computation that did for the medieval astronomer what a slide rule does, in our time, for the engineer. The Equatorie supplies similar details for a companion instrument that allows analogue computation for the places of the planets and the moon in the ecliptic following the Ptolemaic theory and using a set of standard astronomical tables. Unfortunately, details of Chaucer’s scientific education are completely unknown; he is not recorded at Oxford, and if educated in London, perhaps by a Merton man, the details are quite lost and cannot even be guessed.
I. Original Works. Chaucer’s astronomical works are Derek J. Price, ed., The Equatorie of the Planetis (Cambridge, 1955); and Walter W. Skeat, ed., A Treatise on the Astrolabe (London, 1872). His literary works are collected in F. N. Robinson, ed., The Works of Geoffrey Chaucer (Boston, 1957), with a full bibliography on pp. 641–645.
II. Secondary Literature. Chaucer’s astronomical works are discussed in Walter Clyde Curry, Chaucer and the Mediaeval Sciences (New York, 1960); P. Pintelon, Chaucer’s Treatise on the Astrolabe (Antwerp, 1940).
Derek J. de Solla Price