The Light Ages Read online

  The Light Ages

  The Surprising Story of Medieval Science

  SEB FALK

  To Fergus and Vivian

  Bot for men sein, and soth it is,

  That who that al of wisdom writ

  It dulleth ofte a mannes wit

  To him that schal it aldai rede,

  For thilke cause, if that ye rede,

  I wolde go the middel weie

  And wryte a bok betwen the tweie,

  Somwhat of lust, somewhat of lore,

  That of the lasse or of the more

  Som man mai lyke of that I wryte.

  – John Gower

  Contents

  List of Illustrations

  Prologue: The Mystery Manuscript

  1 Westwyk and Westwick

  2 The Reckoning of Time

  3 Universitas

  4 Astrolabe and Albion

  5 Saturn in the First House

  6 The Bishop’s Crusade

  7 Computer of the Planets

  Epilogue: The Mystery Instrument

  Further Reading

  Notes

  Acknowledgements

  Index

  List of Illustrations

  0.1. Image of Derek Price and Peterhouse manuscript 75, from Varsity, 23 February 1952. By permission of Varsity Newspaper, www.varsity.co.uk.

  0.2. Table of mean motions of Mars. Cambridge, Peterhouse MS 75.I, f. 26r. By permission of the Master and Fellows of Peterhouse, Cambridge.

  1.1. Map of notable locations named in this book.

  1.2. Detail from the St Albans watching loft. From Ernest Woolley, ‘The Wooden Watching Loft in St. Albans Abbey Church’, Transactions of the St. Albans Architectural and Archaeological Society (1929), Plate IX.

  1.3. The stars as viewed from the North Pole, equator, and village of Westwick.

  1.4. Historiated initial for October, in a St Albans calendar. Oxford, Bodleian Library MS Auct. D.2.6, f. 6r. By permission of The Bodleian Libraries, The University of Oxford. (plate section)

  1.5. Historiated initial for November, in a St Albans calendar. Oxford, Bodleian Library MS Auct. D.2.6, f. 6v. By permission of The Bodleian Libraries, The University of Oxford. (plate section)

  1.6. Finger-counting positions, in Bede, On Time-Reckoning. London, British Library Royal MS 13 A XI, f. 33v. © British Library Board. All Rights Reserved/Bridgeman Images.

  1.7. The Image of Arithmetic. Gregor Reisch, Margarita philosophica (1503), Book IV frontispiece.

  2.1. St Albans Abbey gatehouse (1365).

  2.2. Constellations explained by Gregory of Tours, De cursu stellarum. Bamberg, Staatsbibliothek MS Patres 61, f. 81r. Photo: Gerald Raab.

  2.3. Euclid and Hermann the Lame with astronomical instruments, drawn by Matthew Paris c.1250. Oxford, Bodleian Library MS Ashmole 304, f 2v. By permission of The Bodleian Libraries, The University of Oxford.

  2.4. Wraparound diagram for a cylinder dial, early fourteenth century. Oxford, Bodleian Library MS Ashmole 1522, f. 181v. By permission of The Bodleian Libraries, The University of Oxford.

  2.5. Abbot Richard of Wallingford with his monumental clock. From the St Albans Book of Benefactors, London, British Library Cotton MS Nero D.7, f. 20r. © British Library Board. All Rights Reserved/Bridgeman Images. (plate section)

  2.6. The ‘strob’ escapement, which governed the St Albans clock. © J. North, 2005, God’s Clockmaker: Richard of Wallingford and the Invention of Time (p. 180), Hambledon Continuum, an imprint of Bloomsbury Publishing Plc.

  2.7. Drawing of part of the gearing for the St Albans astronomical clock. Oxford, Bodleian Library MS Ashmole 1796, f. 176r. By permission of The Bodleian Libraries, The University of Oxford.

  2.8. Hour-striking mechanism from Richard of Wallingford’s clock. Reconstruction (¼-scale) at Whipple Museum of the History of Science, Cambridge. © Jason Bye.

  2.9. Principal face of Richard of Wallingford’s clock. Reconstruction (¼-scale) at Whipple Museum of the History of Science, Cambridge. © Jason Bye. (plate section)

  2.10. The ecliptic with the zodiac constellations, angled at about 23½ degrees to the equator.

  2.11. January page from a St Albans calendar, mid-twelfth century. Oxford, Bodleian Library MS Auct. D.2.6, f. 2v. By permission of The Bodleian Libraries, The University of Oxford.

  2.12. Hand diagram for finding the Golden Number, from Baldwin of Mardochio, Computus manualis (c.1281). Cambridge University Library MS Ii.3.3, f. 14r (c.1300). Reproduced by kind permission of the Syndics of Cambridge University Library.

  3.1. The Liberal Arts, in the Hortus deliciarum by Herrad of Landsberg, abbess of Hohenburg (c.1180), f. 32r. Image by Dnalor_01, Wikimedia Commons, CC-BY-SA 3.0.

  3.2. Frontispiece to Charles Kyrfoth’s Computus manualis (Oxford, 1519).

  3.3. The celestial and terrestrial spheres, in John of Sacrobosco, Computus. Bodleian Library MS Canon Misc. 161, f. 22r (c.1275). By permission of The Bodleian Libraries, The University of Oxford.

  3.4. Gloucester Hall, Oxford. Engraved by David Loggan for Oxonia Illustrata (Oxford, 1675).

  4.1a. The three heavenly planes: horizon, equator and ecliptic.

  4.1b. Ecliptic and equatorial coordinate systems.

  4.2. Torquetum, from Peter Apian, Introductio geographica (Ingolstadt, 1533), f. l.iiii.v.

  4.3. John Westwyk’s annotated diagrams for the Rectangulus (1326) of Richard of Wallingford. Oxford, Corpus Christi College MS 144, f. 80r. By permission of the President and Fellows of Corpus Christi College, Oxford.

  4.4. An English astrolabe. Cambridge, Whipple Museum of the History of Science, Wh.1264 (c.1340).

  4.5. An astrolabe plate for 52 degrees latitude.

  4.6. A plate with scales of azimuth and altitude for latitude 52 degrees, engraved directly into the ‘womb’ of an astrolabe. Cambridge, Whipple Museum of the History of Science, Wh.1264. Photo: John Davis.

  4.7. Rete of the astrolabe. Cambridge, Whipple Museum of the History of Science, Wh.1264. Photo: John Davis.

  4.8. The sharply curved pointer for Algorab. Cambridge, Whipple Museum of the History of Science, Wh.1264. Photo: John Davis.

  4.9. The head and curving tongue of the dog star, Alhabor (Sirius). Cambridge, Whipple Museum of the History of Science, Wh.1264. Photo: Seb Falk. (plate section)

  4.10. Stereographic projection.

  4.11. Back of the astrolabe. Cambridge, Whipple Museum of the History of Science, Wh.1264. Photo: John Davis.

  4.12. Detail of the astrolabe calendar. Cambridge, Whipple Museum of the History of Science, Wh.1264. Photo: Seb Falk.

  5.1. Plan of the surviving buildings of Tynemouth Priory.

  5.2. The horizon at Tynemouth.

  5.3. One of the first chords Ptolemy computed.

  5.4. General theory of the ascensions on the sphere.

  5.5. John Westwyk’s table of oblique ascensions for latitude 55 degrees. Oxford, Bodleian Library MS Laud Misc. 657, f. 42v. By permission of The Bodleian Libraries, The University of Oxford.

  5.6. Opening page of a manuscript from Tynemouth, marked by John Westwyk. Cambridge, Pembroke College MS 82, f. 1r. By permission of the Master and Fellows of Pembroke College, Cambridge.

  5.7. The houses, laid out with the ecliptic on an astrolabe plate for the latitude of Tynemouth.

  5.8. Steps to divide the astrological houses, using a table of right ascensions and a table of oblique ascensions for your latitude.

  5.9. Horoscope drawn up by John Westwyk, based on an example by Masha’allah. Cambridge, Peterhouse MS 75.I, f. 64v. By permission of the Master and Fellows of Peterhouse, Cambridge.

  5.10. The Coldingham Breviary. A Benedictine monk kneels before the Virgin and Child. Text probably in the hand of John Westwyk. London, British Library MS Harley 4664, f. 125v. © British Library Board. All Rights Reserved/Bridgeman Images. (plate section)

  6.1. T-O-style world diagram.

  6.2. Matthew Paris’s map of Britain (c.1255). London, British Library MS Cotton Claudius D VI, f. 12v. © British Library Board. All Rights Reserved / Bridgeman Images. (plate section)

  6.3. Western Europe, part of the Catalan Atlas (probably by Elisha ben Abraham Cresques, 1375). Paris, Bibliothèque nationale de France, MS Esp. 30. (plate section)

  7.1. The first page of John Westwyk’s equatorium treatise. Cambridge, Peterhouse MS 75.I, f. 71v. By permission of the Master and Fellows of Peterhouse, Cambridge.

  7.2. Table of the mean daily motion of apogees and fixed stars. Peterhouse, Cambridge MS 75.I, f. 13v. By permission of the Master and Fellows of Peterhouse, Cambridge.

  7.3. The Sun’s eccentric circle.

  7.4. Radices of the mean apogees of Saturn, Jupiter, Mars, the Sun and Venus, and Mercury. Peterhouse, Cambridge MS 75.I, f. 13v. By permission of the Master and Fellows of Peterhouse, Cambridge.

  7.5. Mean motion of the apogees in years. Peterhouse, Cambridge MS 75.I, f. 7r. By permission of the Master and Fellows of Peterhouse, Cambridge.

  7.6. Ciphered text. Peterhouse, Cambridge MS 75.I, f. 14r. By permission of the Master and Fellows of Peterhouse, Cambridge.

  7.7. Motion of Mars, July 1392 to May 1393.

  7.8. The deferent-epicycle-equant model for a single planet.

  7.9. John Westwyk’s equatorium. Peterhouse MS 75.I, f. 74r. By permission of the Master and Fellows of Peterhouse, Cambridge. (plate section)

  7.10. A combined epicycle.

  7.11a. The ‘epicycle tail’ model of equatorium.

  7.11b. John Westwyk’s equatorium design.

  7.12. Steps in
finding the longitude of a planet using John Westwyk’s equatorium.

  7.13. The theory of the three superior planets and Venus, from Georg von Peuerbach, Theoricae novae planetarum (Venice: Ratdolt, 1482).

  The Light Ages

  Prologue

  The Mystery Manuscript

  Derek Price, they said, was ‘not socially house-trained’.1 It was not easy to fit in, in 1950s Cambridge. Coming from a lower-middle-class Jewish family did not help, and he had no wartime medals to point to, only his training at the undistinguished Southwest Essex Technical College. He had become interested in the history of science while teaching mathematics in colonial Singapore, and sent letters seeking a job as a lecturer. The professors told him to enrol as a student.2 From the day he arrived at Christ’s College, whose alumni included Charles Darwin and the Queen’s cousin, war hero Lord Mountbatten, Price was desperate to prove himself.

  One chilly morning in December 1951, he got his chance. A few months after starting his research on the history of scientific instruments, he had an appointment to visit the medieval library of Peterhouse, Cambridge’s oldest college. There was just one manuscript there that interested him – number 75. It contained – so its nineteenth-century cataloguer had hesitantly guessed – ‘directions for making an astrolabe (?)’.3 It was, as Price later recalled, ‘a rather dull volume . . . and had probably hardly been opened in the last five hundred years it had been in the library’.

  As I opened it, the shock was considerable. The instrument pictured there was quite unlike an astrolabe – or anything else immediately recognizable. The manuscript itself was beautifully clear and legible, although full of erasures and corrections exactly like an author’s draft after polishing (which indeed it almost certainly is) and, above all, nearly every page was dated 1392 and written in Middle English instead of Latin . . .

  The significance of the date was this: the most important medieval text on an instrument, Chaucer’s well-known Treatise on the Astrolabe, was written in 1391 . . . The conclusion was inescapable that this text must have had something to do with Chaucer. It was an exciting chase.4

  The chase got hotter when Price spotted the beginning of a word: ‘chauc’. The rest was buried in the manuscript’s tight nineteenth-century binding, but Price quickly persuaded the Peterhouse librarian to have the binding cut apart. On the day when the disbound leaves returned from the conservators, Price and two distinguished professors were ejected from the hushed library for whooping with raucous delight.5 The full word was indeed revealed to be ‘chaucer’. This ‘dull’ manuscript was a draft instruction manual for a completely unknown scientific instrument. And it was seemingly written by the hand of Geoffrey Chaucer, the greatest English writer before Shakespeare.

  With his characteristic single-minded energy, and equally characteristic disregard for the cautious norms of Cambridge scholarship, Price rushed to publicise his discovery. ‘Chaucer Holograph Found in Library’, trumpeted the university newspaper Varsity, above a collage of the manuscript and Price, with wavy hair and thick-framed glasses, looking a little younger than his twenty-eight years (image 0.1). The Times of London, a few days later, was more hesitant. ‘Possible Chaucer Manuscript: Discovery at Cambridge’ ran its headline. The story quickly spread across the world, in newspapers from Copenhagen to Chennai.6 But was Price right? Or was the Times’s hesitation justified? And why did it matter?

  The shock was not simply that a new work by the famous Canterbury Tales author had been discovered, but that this was a scientific treatise. ‘Was Chaucer a Scientist Too?’ ran the incredulous headline in the Indian newspaper The Hindu. Never mind that historians – including Price himself – were already well aware that Chaucer had written another scientific-instrument manual, the Treatise on the Astrolabe. In the 1950s, just like today, the general view was that the phrase ‘medieval science’ was a contradiction in terms.

  It is often supposed that science began with the Renaissance. In his multimillion-selling book Cosmos (1980), the superstar of popular science, Carl Sagan, drew a timeline featuring a range of famous names and events in the history of science. After a smattering of ancient figures such as Pythagoras and Plato, around the year 400 he marked ‘onset of “Dark Ages” ’. A wide blank space takes us almost to 1500, where we find ‘Columbus, Leonardo’. ‘The millennium gap in the middle of the diagram’, Sagan lamented, ‘represents a poignant lost opportunity for the human species.’7 Sagan never claimed to be a historian – so maybe, one might suggest, he should have left the subject alone – but many who do claim that label have given their readers the same misleading impression. Bookshops are full of titles like ‘The Invention of Science’ that place its birth – in Europe at least – in a time of revolutionary ferment around 1600 that followed the discovery of the New World and the invention of the printing press.8 Even university courses in history of science often begin in that period. One fairly recent book is entitled Science: A History. Though excellent, it begins in 1543, and its first part is named ‘Out of the Dark Ages’.9 The medieval reality, however, is a Light Age of scientific interest and inquiry.

  0.1. Image of Derek Price and Peterhouse manuscript 75, published in Varsity on 23 February 1952. The collaged image placed Price’s head over the crucial ‘chaucer’.

  Curiously, the concept of the Dark Ages itself comes from the medieval world. Early Christians had written of the pagan darkness before the birth of Jesus. Humanist scholars in fourteenth-century Italy took that old Christian metaphor and turned it on its head. They described the darkness of a supposed cultural decline, between the fall of the Roman empire around 400 and their own Renaissance revival of classical learning. For scholars keen to divide human history into easy chunks, it was both convenient and evocative. It gave them an enemy to define themselves against. That became particularly appealing where the Protestant Reformation took hold, and earlier centuries could be mocked as enslaved to Roman Catholic superstition. Introducing a selection of English literature in 1605, the Anglican antiquarian William Camden dismissed the Middle Ages as ‘overcast with darke clouds, or rather thicke fogges of ignorance’.10 The idea of the Dark Ages peaked in the eighteenth century: in his monumental History of the Decline and Fall of the Roman Empire Edward Gibbon described ‘the darkness of the middle ages’, implicitly contrasting them with his own Age of Enlightenment.11* But as historians developed a new appreciation for the brilliance of medieval culture and learning, the term ‘Dark Ages’ began a steady decline. It lingered longer in the English-speaking world, where it served as a shorthand for Britain before the 1066 watershed of the Norman Conquest. Even there, though, it could not last, and historians now prefer the less pejorative term ‘Early Middle Ages’.

  Yet the spectre of the Dark Ages still lurks behind mentions of the medieval world, and especially its scientific achievements. The word ‘medieval’ is routinely used to sum up the barbarous crimes of terrorist groups. Politicians, journalists or judges brandish it metaphorically to condemn torture or female genital mutilation, dismiss an investigation as a ‘witch-hunt’ (though witchcraft trials belong firmly to the Early Modern period), even to bemoan poor cellphone coverage.12 A resurgence of slightly different usage followed the appearance of the phrase ‘get medieval on your ass’ in the ever-quotable 1994 movie Pulp Fiction. When his post as Chief Strategist to President Donald Trump came under threat in August 2017, Steve Bannon reportedly threatened to ‘go medieval on enemies of Trump and his populist agenda’. Bannon’s words aroused annoyance and amusement on social media. The historian and television presenter Dan Snow jokingly asked his Twitter followers if Bannon might ‘Raise a small, unreliable army of ungovernable nobles & poorly equipped, conscripted peasants and immediately get dysentery?’ He followed that tweet with ‘Lack the most basic understanding of scientific method, embrace quackery & astrology and depend on an imagined deity to bring you victory?’13

  That second tweet from Snow, however light-hearted, reminds us how negative stereotypes of medieval science have lingered. It is understandable. Our eyes are drawn to the most striking objects, and our minds to simple summaries. In an age when the world’s tallest building was Lincoln Cathedral, who would doubt the immense power of religious faith? But belief in God never prevented people from seeking to understand the world around them. Loyalty to texts and traditions never meant the rejection of new ideas. Channelling money and creative energies into religious art and architecture never restricted the range of medieval people’s interests. The relationship between faith and the study of nature was – and remains – a complex one, as we shall see throughout this book. Disputed ideas have occasionally caused conflict, of course. But to imagine ‘science’ and ‘religion’ as two separate, inevitably antagonistic opponents, or to suggest that such closed-mindedness as does exist has always been on the side of religion, is far too simplistic. The Middle Ages were much more than battles and black boils.