1 ‘ John Dee Studied as an English Neoplatonist,’ 2 vols. (Diss. London University, 1952). A very brief version of this paper was read at the Sixteenth Century Studies Conference, November 1, 1975. I am grateful to Charles B. Schmitt, who read an early draft of this paper and offered many helpful suggestions.

2 John Dee: The World of an Elizabethan Magus (London: Routledge & Kegan Paul, 1972).

3 French, p. 15, quoting Thomas Smith, Vita Joannes Dee (1707).

4 Shumaker, Wayne, The Occult Sciences in the Renaissance (Berkeley: University of California Press, 1972), p. 261 Google Scholar.

5 Calder, I, i, 7-18, 41-67, 126, 139.

6 Yates, Frances A., Giordano Bruno and the Hermetic Tradition (Chicago: University of Chicago Press, 1964), p. 150 Google Scholar. Yates, Frances A., ‘The Hermetic Tradition in Renaissance Science,’ in Art, Science, and History in the Renaissance, ed. Charles S. Singleton (Baltimore: Johns Hopkins Press, 1968), pp. 259, 261-62Google Scholar. Yates, Frances A., Theater of the World (London: Routledge & Kegan Paul, 1969), p. 5 Google Scholar.

7 French, pp. 2-3.

8 N. H. Clulee, ‘ “The Glas of Creation“: Renaissance Mathematicism and Natural Philosophy in the Work of John Dee’ (Diss. University of Chicago, 1973), pp. 26-27, 52-67.

9 Calder, 1, 247. French, p. 28. The issue is not the existence of Neoplatonic elements or Hermetic tendencies in some of Dee's works, but how these are used. Calder, because he considered Renaissance Neoplatonism to have had a positive relation to the development of early modern science, chose this element as the basis for developing an idea of Dee's philosophy and then interpreted Dee's writings in terms of this rather a priori construct (Calder, I, 7-18). French does the same thing with Hermeticism, using almost exclusively among Dee's works the Monas hieroglyphica (Antwerp: Willem Silvius, 1564) and then reading these same ideas back into Dee's earlier works (French, pp. 62-88, 93-103). In the present author's study of Dee's mathematicism and natural philosophy, an account of Dee's mathematical philosophy derived from his ‘Mathematicall Praeface’ to Euclid, The Elements of Geometrie, tr. H. Billingsley (London: John Day, 1570), provided the basis for studying Dee's application of mathematics to nature. In the case of Dee's grading, which appeared in the ‘Mathematicall Praeface’ ( Clulee, N. H., ‘John Dee's Mathematics and the Grading of Compound Qualities,’ Ambix, 18 [1971], 178–211 CrossRefGoogle Scholar), this was quite legitimate, but reading this same philosophy back into Dee's earlier works (Clulee, ‘ “The Glas of Creation”,’ chs. III and IV), while plausible and possibly illuminating, renders such interpretation subject to anachronistic distortions.

10 Dee has listed in several places those works that he claims to have written: Dee, John, Propaedeumata aphoristica… , de Praestantioribus quibusdam Naturae Virtutibus (London: Henricus Suttonus, 1558)Google Scholar, sig. *iii^r-v; Dee, John, The Compendious Rehearsall … anno 1592, November 9, in Autobiographical Tracts of Dr. John Dee, ed. James Crossley, Chetham Society Publications, 24 (Manchester, 1851), 24–27 Google Scholar; and John Dee, A Letter… Apologeticall … 1592, in Autobiographical Tracts, pp. 73-77. Compare these with the bibliography of extant works in French, pp. 210-217.

11 There is little dispute that Renaissance Neoplatonism was a specific philosophical development involving the conscious return to ancient sources and the espousal of characteristic positions. Of the extensive literature, see Kristeller, P. O., ‘Renaissance Platonism,’ in his Renaissance Thought: The Classic, Scholastic and Humanist Strains (New York: Harper Torchbooks, Harper & Row, 1961), pp. 57–59 Google Scholar. These specific characterizations will be the criteria for judging Dee's Neoplatonism. Hermeticism has more often been the subject of confusion. The term is sometimes applied to any presence of vaguely ‘occultist’ ideas; at other times the term is limited to the specific philosophical and theological outlook developed in the Renaissance through the revival of the Corpus hermeticum. It is this more specific understanding as developed by Garin, Eugenio, ‘Magic and Astrology in the Civilization of the Renaissance,’ in his Science and Civic Life in the Italian Renaissance, tr. Peter Munz (New York: Anchor Books, 1969), pp. 148–154 Google Scholar; and Yates, Giordano Bruno, pp. 17-18, 58, that will prevail in this paper.

12 In the course of this investigation I shall deal with the Propaedeumata aphoristica in some detail, but this is not intended to be a systematic exposition of that work. Such treatments exist in Calder, I, 501-528; in Clulee,’ “The Glas of Creation”,’ ch. III; and in Mary Ellen Bowden, ‘The Scientific Revolution in Astrology: The English Reformers, 1558-1686’ (Diss. Yale University, 1974), pp. 63-78.

13 John Dee, ‘A Necessary Advertisement, by an Unknown Friend, Given to the Modest, and Godly Reader: Who also Carefully Desire the Prosperous State of the Commonwealth of this Brytish Kingdom, and the Politicall Securitie thereof,’ from John Dee, General and Rare Memorials pertayning to the Perfect Art of Navigation: Annexed to the Paradoxal Compas, in Playne Invention thereof (1577), in Autobiographical Tracts…, p. 56. In quotations from manuscripts and early editions, abbreviations and contractions have been expanded and modern typographical usage has been followed with respect to i/j, u/v, and vv. The idiosyncratic English spelling of John Dee and his sixteenth-century publishers has not been modernized.

14 The term ‘astrology’ did not have a simple, unambiguous meaning in the sixteenth century, or earlier for that matter. It could mean, as it does presently, judicial astrology—it will refer to the study of celestial influences, although it should become apparent that to Dee astrology primarily involved the theoretical and mathematical study of the influences operating on all things in the natural world and only secondarily the casting of particular horoscopes. Thus Dee does not use the word ‘astrology’ in the Propaedeumata, but indicates that its subject is ‘certain outstanding virtues of nature.’ In his Mathematicall Praeface to the Elements ofGeometrie of Euclid of Megara, introd. by Allen G. Debus (1570; facsimile rpt. New York: Science History Publications, 1975), sig. biii, he defines astrology as ‘… an Arte Mathematicall, which reasonably demonstrateth the operations and effectes, of the naturall beames, of light, and secrete influence: of the Sterres and Planets: in every element and elementall body… .'

15 Dee, The Compendious Rehearsall… , pp. 5-6.

16 Hackett, M. B., Original Statutes of Cambridge University: The Text and its History (Cambridge: Cambridge University Press, 1970), pp. 298–303 Google Scholar, reconstructs the basic curriculum as of ca. 1500 and implies that this was not formally changed prior to Dee's completion of his studies. In the third year this program involved lectures on Aristotle's Physica and one of the following: De generatione, De anima, De caelo, Meteorica, or Ethica. In the fourth year lectures were on either Aristotle's Physica or Metaphysica and again one of the additional works listed for the third year. Jardine, Lisa, ‘The Place of Dialectic Teaching in Sixteenth-Century Cambridge,’ Studies in the Renaissance, 21 (1974), 47–49 Google Scholar, n. 38, gives a course of study dating from the 1640's but she sees no reason to doubt that this was similar to a program for the 1560's and 1570's. In this program of studies the third year was devoted to Aristotle's Organon, and to his Physica and Ethica; and the fourth year to his De anima, De caelo, and Meteorologica. Between the earlier and the later programs there is very little difference in matter, although there may have been changes in the way Aristotle was taught and interpreted which have not been investigated. Nevertheless, it seems safe to conclude that the curriculum was roughly similar while Dee was at Cambridge.

17 Vocht, Henry de, History of the Foundation and the Rise of the Collegium Trilingue Lovaniense, 1517-1550, 4 vols. (Louvain: Bibliothèque de l'Université, 1951-55), II, 543, 545 and n. 2, 560-61Google Scholar.

18 Ibid., pp. 5-8.

19 Ibid., p. 10.

20 Johnson, Francis R., Astronomical Thought in Renaissance England (Baltimore: Johns Hopkins Press, 1937), pp. 87–90 Google Scholar.

21 Dee, The Compendious Rehearsall… , pp. 4-5. The Royal College of Physicians, London, possesses a copy of Abū Ali Yahyā al-Khayyāt, Albohali arabis … De iudiciis nativitatum (Nuremberg: Ioannis Montani, 1546), bound with Ioannes Hispalensis, Epitome Totius Astrologiae. This copy contains weather notes by Dee dated 1548, which are apparently his earliest such observations.

22 Dee, The Compendious Rehearsall… , p. 24; Dee, A letter … Apologeticall, p. 74. This work has apparently not survived.

23 Dee, Propaedeumata aphoristica, sig. *i^r-v. Cf. Dee, Mathetnaticall Praeface, sigs. biii^v-biiij: ‘I was, (for *21. yeares ago) by certain earnest disputations, of the Learned Gerardus Mercator, and Antonius Gogava, (and others) thereto so provoked.’

24 Mercator, Gerard, Historia mundi: or Mercator's Atlas. Containing his Cosmographical Description of the Fabricke and Figure of the World … , Englished by W.S. [William Sparke] (London, 1635), pp. 26, 42Google Scholar.

25 Gerard Mercator to H. de Rantzau, May 1585, in van Durme, M., Correspondance Mercatorienne (Anvers, 1959), p. 192 Google Scholar; and F. van Ortroy, ‘Biobibliographie de Gemma Frisius, fondateur de l'école beige de géographie, de son fils Comeille et de ses neveux les Arsenius,’ Académie royal de belgique, Classe des lettres et des sciences morales et politiques, Mémoires, 11:2 (1920), 23.

26 Cl. Ptolemaei … Operis quadripartiti. in latinum sermonem traductio: adjectis libris posterioribus… de sectione conica … quae parabola dicitur, deque speculo ustorio … cum praefatione D. Gemma Frisii (Louvain, 1548). The De speculo ustorio is actually a very corrupt Latin version of a treatise by Ibn al-Haytham on parabolic burning mirrors; see J. L. Heiberg and E. Wiedemann, ‘Ibn al Haitams Schrift über parabolische Hohlspiegel,’ Bibliotheca Mathematica, 3rd ser., 10 (1910), 201-237, at 231. I have been unable to identify the other work. It is also interesting to note that both of these works were attributed to Roger Bacon, who was an important influence on Dee's interest in optics. See Wiedemann, Eilhard, ‘Roger Bacon und seine Verdienste um die Optik,’ in Andrew G. Little, ed., Roger Bacon Essays (1914; rpt. New York: Russell and Russell, 1972), p. 187 Google Scholar.

27 These figures are based upon books and manuscripts that I have been able to identify as having been definitely owned by Dee and bearing a date. Most of these are in the Royal College of Physicians, London, and University Library, Cambridge. Those from the Royal College of Physicians are listed in W. R. B. Prideaux, ‘Books from Dee's Library,’ Notes and Queries, 9th ser., 8 (1901), 137-138; 10th ser., 1 (1904), 241-242. Those in University Library are noted in List of Books with Signatures of Dee, University Library, Cambridge, MS. Add. 4403 (109). In addition, Dee acquired in this period the following: Plinius Secundus, C., Liber II. C. Plinii de mundi historia … (Frankfurt: Petri Brubachii, 1543)Google Scholar, London, British Museum, shelf-mark c.107.d.22; Alberti Magni summa naturalium … , London, British Museum MS. Harley 536; Antiochus, [Greek commentary on the Tetrabiblos of Ptolemy], Oxford, Bodleian MS. Arch. Selden B.8; and Roger Bacon, [Various works], Oxford, Bodleian MS. Digby 76. I have examined each of these items. Mr. Andrew Watson of University College, London, has kindly informed me of the following additional manuscripts that Dee acquired prior to 1556: Oxford, Bodleian MS. Digby 119 [alchemical]; Dublin, Trinity College MS. D.4.27 (441) [various scientific works]; Dublin, Trinity College MS. D.4.30 (444) [astronomical tables]; Cambridge, Magdalene College MS. Pepys 1207 [Roger Bacon]; and British Museum MS. Cotton Vesp. A.n [Roger Bacon]. While there may be other such material that can definitely be dated, it has not come to my attention. The thirty-six items can be divided among categories as follows, with the date in parenthesis indicating when that category first appeared: astrology (1548), 12; Aristotelian philosophy (1547), 7; mathematics (1551), 4; medicine (1550), 4; chemistry/alchemy (1551), 2; religion (1554), 1; Greek grammar (1551). 1; art (1550), 1; moral philosophy (1550), 1; navigation (1552), 1; miscellaneous, 2. Prior to 1547 there exist only two such items, a Bible acquired in 1538 and a grammar in 1544. I certainly realize that thirty-six is not a very significant number statistically, that hitherto unidentified or undated material might upset these figures, and that Dee undoubtedly read additional things; but this is all the evidence currently available.

28 The five items in question are the Albohali and the Hispalensis noted above, n. 21, plus two other books in the Royal College of Physicians: Ptolemy, Quadripartitium [Tetrabiblos], and Cardano, Libelli quinque, both heavily annotated, and the Pliny noted above, n. 27, also heavily annotated on astrological questions.

29 Dee, Propaedeumata aphoristica, sig. *iii^r-v; Dee, The Compendious Rehearsall…, pp. 24-25; Dee, A Letter … Apohgeticall, pp. 74-75.

30 Oxford, Corpus Christi College Ms. 191, fols. 77^v-90. This comprises several lists, headed variously: ‘Libri antiqui scripti quos habeo anno 1556,’ ‘Reddenda anno 1558 in festo Michaelis. Antiqua exemplaria quos habui a Collegio S. Petri Cantabrigiae 1556. 6 Maii,’ ‘Recepi a doctore Hathar eodem tempore, reddenda in festo Michaelis 1558. ea quae sequuntur ut catalogus prefixus enumerat,’ ‘Libri quos habeo in uno volumine in Collegio Reginali Oxoniae anno 1556. 12 Maii Magistro Morreno et Magistro Carie mecum praesentibus. Et Magister Knipe eiusdem collegii socius nobis tradidit, ita quod dicti magistri et episcopus Londiniensis pro eiusdem voluminis redditione onus omne in se susciperent.’ ‘Ex bibliodieca Laelandi emi pro 30 solidis hos sequentes libros 1556. 18 Maii. Londinii,’ ‘Authores alchymici quos perlegi anno 1556 a mense Julii.'

31 Some of the manuscripts listed in the later catalogue of his library, Catalogus librorum Bibliothecae (Externae) Mortlacensis D. John Dee. A^°. 1583 6° Sept., London, British Museum, MS. Harley 1879, are very similar to manuscripts in the Corpus Christi College lists, indicating that Dee may have failed to return some at all.

32 The breakdown of the 249 items of the lists in Corpus Christi College MS. 191 by category is as follows in order of prominence: alchemical, 76; mathematics, 40; astronomy, 29; optics, 29; astrology, 11; Aristotelian philosophy, 10; medicine, 9; mechanics, 9; Platonic philosophy, 3; gradation of qualities, 3; magic, 3; music, 3; memory, 2; cosmography, 1; magnetism, 1; meteorology, 1; and miscellaneous unidentifiable works, 19.

33 I have identified several items on each subject, although mathematical works tend to predominate: see British Museum MSS. Harley 1, Cotton Tiberius c.v., and Royal 12 B XXII; Oxford MSS. Corpus Christi College 234, 254, and 293, Sloane 2128 and 2325, and Digby 71; Cambridge, St. John's College MS. 171; Lambeth Palace MS. 67; British Museum shelf-mark c122.bb.35; and Prideaux (n. 27) for other books. Again, I am much indebted to Andrew Watson for a number of manuscript references.

34 Dee, Propaedeumata aphoristica, sig. °iii^r-v; Dee, The Compendious Rehearsall…, pp. 24-25; Dee, A Letter … Apologeticall, pp. 74-75. Since in the Propaedeumata he lists all three optical works, he was undoubtedly mistaken in the later lists when he gives the date for one as 1559. Fragments of the De speculis comburentibus, and another optical work are preserved in British Museum MS. Cotton Vitellius c.VII.

35 Dee, Propaedeumata aphoristica, sig. *iii^r-v: ‘Speculum unitatis: sive Apologia pro Fratre Rogerio Bachone Anglo: in quo docetur, nihil ilium per Daemoniorum auxiliafecisse, sed Philosophumfuisse maximum: naturaliterque, & modis homini Christiano licitis, maximas fecisse res: quas, indoctum solet vulgus in Daemoniorum referre facinora.’

36 Corpus Christi College MS. 191, fols. 77^v, 78^v, 79^r-v, 82, 83, 88^v. British Museum MS. Cotton Tiberius c.v.

37 Sixty-one of the seventy-six alchemical titles in Corpus Christi College MS. 191 are grouped in one list, ‘Authores alchymici quos perlegi anno 1556 a mensejulii.’ From this it is doubtful how carefully Dee could have considered these at that time.

38 Dee, Propaedeumata aphoristka, aphorism LII. John Dee, Monas hieroglyphica, in Josten, C. H., ‘A Translation of John Dee's Monas hieroglyphica (Antwerp, 1564)Google Scholar, with an Introduction and Annotations,’ Ambix, 12 (1964), 136-137 (fol. 7^V).

39 Dee, Monas hieroglyphica, pp. 146-147 (fol. 10).

40 Ibid., pp. 146-147 (fol. 10).

41 For example, the Cabalistic manipulation of the Monad symbol in the Monas hieroglyphica depends very directly upon Johannes Augustinus Pantheus, Voarchadumia contra alchemiam: ars distincta ab archimia, & sophia: cum additionibus: proportionibus: numeris: & figuris opportunis (Venice, 1530), which was signed and dated by Dee in 1559 and contains numerous annotations involving the symbols of the Monas hieroglyphica. Further, the numerology of the Monas derives from Johannes Trithemius Qosten, ‘Introduction’ to ‘A Translation of John Dee's Monas,’ pp. 108-110), whom Dee discovered only in 1562 (John Dee, Letter to Sir William Cecyl, February 16, 1562, in Philobiblon Society, Bibliographical and Historical Miscellanies 1, no. 12 [1854], 1-16). For Dee's work in Cabala, see Dee, Monas hieroglyphica, pp. 134-137 (fol. 7^r-v).

42 Compare the texts of the following aphorisms in the 1568 edition of the Propaedeumata with those of the 1558 edition: II, XVIII, XXVI, LXXII, LXXVII.

43 Dee, The Compendious Rehear sail … , pp. 4-5. Dee's notes are on the two leaves following the last printed page in the Albohali… de iudiciis nativitatem in the Royal College of Physicians noted above, n. 21. The table is headed ‘Medii motus planetarum. 1548 primo Novembris in meridie.’ The weather observations are headed ‘Lovanii. Observationes factae de Aeris variis affectionibus & mutationibus Ann. Domini 1548. Mense Aug.’

44 These diaries are found in Stadius, Ioaimes, Ephemerides novae (Cologne, 1570)Google Scholar, and Maginus, Ioannes Antonius, Ephemerides coelestium motuum (Venice, 1582)Google Scholar, Oxford, Bodleian MSS. 487 and 488 respectively.

45 See the notes and underlinings in C. Plinius Secundus, Liber II. C. Plinii de mundi historia, cum commentariis Iacobi Milichii (Frankfurt: Petri Brubachii, 1543), British Museum shelf-mark c.107.d.22, fol. 108^v. This work also contains an ‘Oratio de dignitate astrologiae’ by Milichus. This is signed by Dee and dated 1550.

46 Ibid., fol. 75^r-v.

47 See the long note in Dee's hand, dated 1551, on the flyleaf of Ptolemy, Claudius, Quadripartitium (Venice, 1519)Google Scholar, which is in the Royal College of Physicians, London. In the sense that man is strictly part of his environment, Dee's astrological theory included genethlialogy, or the casting of individual nativities, a practice which Dee engaged in all of his life. A number of horoscopes of nativities for the years 1564 to 1566 can be found in Oxford, Bodleian Library MS. Ashmole 337, fols. 20-57^v; and Dee's diaries, Bodleian MSS. Ashmole 487 and 488, contain references to the time and place of birth for numerous individuals, undoubtedly preparatory to casting horoscopes. Dee's formal writings on astrology, however, are confined to general theory and do not deal with detailed procedures for casting horoscopes.

48 Aristotle, Meteorologica, tr. Webster, E. W., in The Works of Aristotle, ed. David Ross (12 vols., Oxford: Clarendon Press, 1908-31), III, 339a11-33Google Scholar.

49 Ibid., 340a25-35. Aristotle, De generatione et cormptione, tr. H. H. Joachim, in The Works of Aristotle, II, 336a15-336b5.

50 Ptolemy, Claudius, Tetrabiblos, tr. E. E. Robbins (Cambridge, Mass.: Harvard University Press, 1940), pp. 5–9 Google Scholar.

51 Ibid., pp. 9-11.

52 Ficino, Marsilio, De vita coelitus comparanda, Bk. 3 of De vita libri tres, in Opera (Basel, 1561), pp. 493–574 Google Scholar. Pomponazzi, Pietro, De naturalium effectuum admirandorum causis, seu de incantationibus, in Opera (Basel, 1567)Google Scholar.

53 Yates, Giordano Bruno, pp. 65-66. Walker, D. P., Spiritual and Demonic Magic from Ficino to Campanella (London: Warburg Institute, 1958), pp. 12–14 Google Scholar.

54 Ficino, p. 473 [sic].

55 Ibid., p. 534.

56 It should not be surprising to find Aristotelian elements as important components in Dee's natural philosophy, since the major focus of the curriculum at Cambridge in the early sixteenth century was still Aristotle's philosophy. Two of the earliest works acquired by Dee, Barbaro, Ermolao, Compendium scientiae naturalis, ex Aristotele (Venice, 1547)Google Scholar. signed and dated by Dee in 1547 and now in University Library, Cambridge, and Albertus Magnus, Summa naturalium, British Museum Ms. Harley 536, signed and dated by Dee in 1549, both reflect this focus.

57 Oxford, Bodleian Library Ms. Ashmole 337, fols. 51-57. These notes are of several types, some being reading notes, some are collections of opinions on a single subject, and some, headed ‘Mea,’ are Dee's own opinions. Calder, 1, 338-403, discusses these notes in great detail and relates them closely to Pomponazzi's De immortalitate animae.

58 Ms. Ashmole 337, fols. 51^v, 52^v, 56^v, citing the Metaphysica, the Physica, the Meteorologia, the De anima, and the De generatione animalium. The other author cited is apparently Agostino Nifo (fol. 57^v), who defended the immortality of the soul against Pomponazzi; but Dee seems not to accept Nifo's view, since he immediately notes Aristotle's contradictory opinion.

59 Ibid., fols. 51^v-52^v.

60 John Dee, the notes representing his own thoughts, beginning ‘Mea,’ Ms. Ashmole 337, fol. 56^v: ‘1. quorsum erit perennis? an ut substantia ociosa sine opere? sed aliud opus denuo habebit. nee prorsus sensibus utetur aut vita … . 4. non est incorporea. quomodo a corporis societate in contrariam suae naturae traduci posset, si nee qualitas est corporis, nee forma, nee affectus nee potentia est.’

61 Ibid., fol. 56^v: ‘9. Aristoteles de generatione animalium 2 capite 5 affirmat omnes animas potentia in semine sitas. ibi est suus actus quia est potentia.’ Fol. 57: ‘10. si sit exterius et non in semine, et accedat ubi propria eius operatic quia omnis forma habet operationem propriam. quare et illam iuncta corpori servabit. 11. si est eternum non potuit corpori contingere. quia apud Aristotelem, eterno nihil contingit.’ Cf. Aristotle, De generatione animalium, tr. A. Piatt, in The Works of Aristotle, v, 741a6-12.

62 Ibid., fol. 56^V: ‘2. si esset animus immortalis fieret quia ratione utitur. at ratio differentia est hominis qua distinguitur a reliquis animantibus. ratio vera est nihil aliud quam vis quaedam resiliendi ex una imaginatione in aliam, rum ex cognitione in cognitionem.’

63 Ibid., fol. 56^v: ‘7. intellectus movetur secundum rem. res vero est sensibilis. igitur per conditionem rei sensibilis se habet intellectus. pereunt sensibilia igitur et intellectus. 8. nee agens nee patiens intellectus nobis perdest [sic], licet uterque sit immortalis. nam sine patiente agentem, sine sensu patiente Aristoteles negat quicunque intelligere. extincto igitur sensu etiamsi supersit uterque, neuter tamen intelligit. dicit enim ille oportere intelligentem imagines rerum per sensum interiorem formatas contemplari.’ Cf. Aristotle, De anima, tr. J. A. Smith, in The Works of Aristotle, III, 403a1-25.

64 Calder, I, 339-340.

65 Ibid., I, 339-342.

66 Ibid., I, 293-303.

67 Ms. Ashmole 337: on fols. 20-50^v the horoscopes are continuous, each occupying one-half of a page. Following fol. 51, where the notes begin, the horoscopes are scattered, upside down, and smaller. This could be the result of Dee's attempt to avoid conflict with the already existing notes by placing the horoscopes in already existing spaces between the notes. Further, the notes on fol. 51 are not complete, beginning in the middle of ch. 3 of some work that Dee was summarizing. The notes on the earlier material are missing, indicating that the horoscopes and the notes on the soul may have originally been two separate notebooks.

68 Calder, I, 339-340. Calder's interpretation of Dee's notes on the soul as evidence of his break from Aristotelian naturalism is designed to support his general thesis that Dee represents a progressive tradition of scientifically oriented Neoplatonism that leads to seventeenth-century mechanistic science. To illustrate Dee's motives, Calder claims that the philosophy of Ralph Cudworth (1617-88) clearly and explicitly states the issues with which Dee was concerned and the solution Dee sought. Cudworth advocated an atomistic and mechanistic physiology not only because it rendered natural things more intelligible than the older concepts of matter and form but also because it could not give a naturalistic account of all phenomena and particularly those to which the name soul is given. By accepting a mechanistic view of nature, Cudworth could thus be a ‘modern’ and also a Platonist, and Calder argues that he did this in order to defend the immortality and spirituality of the soul. Calder likewise argues that Dee also rejected the Aristotelian categories of matter and form to safeguard the immortality of the soul and that this put Dee in the progressive tradition leading to seventeenth-century mechanism (ibid., 1, 349-350). This may be the crucial aspect of Calder's argument. If these notes represent Dee's true opinions at some point, they would indicate, according to Calder, that Dee took a position very close to that of Pietro Pomponazzi, including the naturalistic yet magical causality of the De incantationibus. Now Calder has previously developed the thesis that Renaissance naturalism, typical of Pomponazzi, was of no significance for the progressive developments in sixteenth-century natural philosophy (ibid., I, 44-48). Perhaps here, as elsewhere, Calder is trying to disassociate Dee as much as possible from Pomponazzi and naturalism in order to associate him with developments leading to the mechanistic science of the seventeenth century.

69 See Dee's statement ‘hominem ut fecit natura—corpus, spiritus, anima,’ in Ptolemy, Quadripartitium, fol. 10^v (Royal College of Physicians’ copy).

70 Dee, Propaedeumata aphoristka, aphorisms XVI and XVII. Cf. Aristotle, Meteorologia, Works, III, 339a11-33. Henceforth, references to the Propaedeumata (abbreviated P.A.), noting either the Roman numerals of individual aphorisms or the signatures of the prefatory material, will appear parenthetically in the text. The interpretations that follow are based upon the readings of the 1558 edition, except where editorially improved upon in the 1568 edition, but ignoring the substantive additions in the 1568 edition, as many of these represent elements foreign to Dee's thought in 1558.

71 Cf. Aristotle, Meteorologia, Works, III, 340a25-35, 341a15-25; Aristotle, De generatione et corruptione, Works, II, 336a15-336b5.

72 A similar proposition was also used by Pomponazzi to develop his conception of the universe in which all miracles and extraordinary interventions of demons, angels, and other separate intelligences were excluded (Pomponazzi, De naturalium effectuum admirandorum causis, seu de incantationibus, Opera, pp. 115, 315).

73 John Dee, Letter to William Camden, August 7, 1574; Oxford, Bodleian Library MS. Ashmole 1788, fol. 71^r-v: ‘At in primo statim aphorismo meo (ut caetera taceam) artis cujusdam magna iactum est fundamentum firmum, quae (brevissime) iisdem meis explicata est Aphorismis.’ In this letter he also indignantly denies charges by someone that his aphorisms plagiarized the work of Urso. Dee did have an Aphorismi Ursonis in 1556 (Corpus Christi College MS. 191, fol. 83), but an examination of the text (Gebhard von Jagow, ed., Die naturphilosophischen, ausführlich kommentierten Aphorismen des Magister Urso von Calabrien aus der medizinischen Schule von Salerno [Leipzig: Emil Lehman, 1924]) indicates that while Dee's first aphorism is similar in intent to the first aphorism of Urso, its wording is different and that the similarity of these two works ends at that point.

74 Cf. Dee, Mathematicall Praeface, sigs. bij^v-biij.

75 Dee clearly supposed that all celestial bodies were self-luminous, see P.A., LIII, C.

76 These are partially in Greek. Translations can be found in Calder, I, 510-511.

77 Yates, Giordano Bruno, pp. 1-19. The following edition is standard and served as the basis for my search: Trismégiste, Hermès, Corpus hermeticum, tr. and ed. A. D. Nock and A.-J. Festugière, 2nd ed., 4 vols. (Paris: Société d'Edition ‘Les Belles Lettres,’ 1960)Google Scholar.

78 Naturalism in this sense, however, should not imply a mechanical or physical causality to the exclusion of other influences that Dee considered natural. According to Dee, all influences were natural other than the intervention of angels or demons acting contrary to the laws of nature. It will become apparent that I disagree with Calder, who finds in the Propaedeumata a mechanistic universe that points toward the type of mechanism that was so significant in the seventeenth century (Calder, I, 5-7, n. 5). The causality of the Propaedeumata can be called a mechanism, but it is much closer to that of the naturalistic cosmologies of the Renaissance, imbued with secret, magical forces, than to those of the science of the seventeenth century.

79 ‘Sicut primi motus privilegium est, ut sine ea torpeant omnes religui, sic primae & praecipuae qualitatis sensibilis, (nimirum LUCIS) ea est facultas, ut sine ea caeterae qualitates agere nihil possint.’ See also P.A., XV. Calder, I, 506, reads XXII as if it referred only to light awakening the faculties of the mind. It would seem, however, to refer to the action of all qualities of the natural world.

80 This was the general presupposition of all medieval optics. Species diffuse throughout the surrounding medium by a process of self-reproduction. Species were not thought of as corpuscular, and rays had no real existence, but this diffusion could be described or represented by rays. Since the propagation of species, including light, could be described as rays, it was possible to reduce optical problems to ray geometry—that is, to a purely geometrical optics in which lines drawn according to geometrical rules were used to represent optical phenomena. See Lindberg, David C., ‘Introduction,’ in John Pecham, John Pecham and the Science of Optics: Perspectiva communis, ed. and tr. David C. Lindberg (Madison: University of Wisconsin Press, 1970), pp. 39–40 Google Scholar. Also see sec. IV below for a more detailed treatment of Dee's background on this issue.

81 Dee, Mathematicall Praeface, sig. bi.

82 Crombie, A. C., Robert Grosseteste and the Origins of Experimental Science, 1100-1700 (Oxford, Clarendon Press, 1962), pp. 104, 106Google Scholar; Eastwood, Bruce S., ‘Medieval Empiricism: The Case of Grosseteste's Optics,’ Speculum, 43 (1968), 307–308 CrossRefGoogle Scholar. The major expressions of these ideas are found in Robert Grosseteste and Roger Bacon who will be discussed below, sec. IV, in connection with the sources upon which Dee relied for his ideas.

83 Crombie, pp. 104, 109. Eastwood, ‘Medieval Empiricism,’ pp. 307-308.

84 Dee, Mathetnaticall Praeface, sig. bi.

85 Lindberg, ‘Introduction,’ John Pecham … , pp. 36-38.

86 A spherical body clearly emits an infinite number of rays in all directions but the only rays that affect any one point will be those defined by the cone whose vertex is that point and whose base is the circular portion of the sphere visible from that point. The rays from an agent to the surface of a patient form an infinite number of such cones with vertices touching all points on the surface of the patient. Again, for any one point on the patient, only one of these cones is considered.

87 The widespread adoption of the Ptolemaic system in medieval astronomy, both in Islam and later in the West, based on a part of Ptolemy's Planetary Hypotheses that survived only in Arabic, allowed for the computation of the absolute distances of all planetary distances and implied that the planets vary in distance from the center of the universe and from the earth. See Toomer, G. J., ‘Introduction,’ in Campanus of Novara, Catnpanus of Novara and Medieval Planetary Theory: Theorica planetarum, ed. and tr. Francis S. Benjamin, Jr., and G.J. Toomer (Madison: University of Wisconsin Press, 1971), pp. 53–56 Google Scholar. Campanus adopts this system in detail, and Dee was most likely aware of it, since he had a copy of Campanus’ work as early as 1556 (Corpus Christi College MS. 191, fol. 81^v) in addition to a number of other medieval astronomical works.

88 Dee, Mathematicall Praeface, sig. biij^v.

89 In 1551 Dee wrote a work, which he did not publish and which is now lost, in which he apparently dealt in greater detail with the determination of the type of measurements that he calls for in the Propaedeumata, entitled De nubium, solis, lunae, ac reliquorum planetarum, immo ipsius stelliferi coeli, ab infimo terrae centro, distantiis, mutuisque intervallis, et eorundem omnium magnitudine liber , ad Edoardum sextum, Angliae regem (P.A., sig. *iii; Dee, The Compendious Rehearsall, p. 26; Dee, A Letter … Apologeticall, pp. 74-75). This work may in part consist of or be a draft of the method for finding stellar parallaxes that Dee published after the appearance of the nova of 1572 (John Dee, Parallacticae commentationis praxeosque nucleus quidam [London: Johannem Dayum, 1573]). Calder, 1, 511, believes that a work by Joannes Fransiscus Offusius, De divina Astrorum facultate (Paris, 1570), which Dee claimed was a plagiarism of his Propaedeumata but which is clearly more than that, is, in a sense, a supplement to Dee's work containing the exact scientific and mathematical knowledge underlying Dee's general statements. Mary Ellen Bowden of Yale University, with whom I have discussed Dee and sixteenth-century astrology on a number of occasions, has discussed Offusius’ astrology and its relation to Dee in ‘The Scientific Revolution in Astrology,’ pp. 78-89.

90 Dee seems to intend what Roger Bacon says in more detail and more clearly in The Opus Majus of Roger Bacon, ed. T. H. Bridges, 2 vols. (Oxford: Clarendon Press, 1897), 1, 126-127.

91 See below, sec. IV.

92 Dee seems to be inconsistent here. At this point he implies that the speed of the moon increases its effects on humidity, but earlier he indicates that astral influences are stronger in proportion to the length of time the influence is impressed, that is, on the slowness of the motion.

93 Dee lists the Bacon treatise among those manuscripts he possessed in 1556 (Corpus Christi College MS. 191, fol. 78^v), and he discusses it in Dee, Mathematical Praeface, sigs. *iij-*iiij. I have discussed Dee's treatment of Bacon's grading at length in ‘John Dee's Mathematics and the Grading of Compound Qualities,’ Atnbix, 18 (1971), 178-211.

94 Clulee, ‘John Dee's Mathematics… ,’ pp. 180-181.

95 In these Dee solves several problems in permutations and combinations, and discusses the method for such calculations. The significance of Dee's work in this area was emphasized to me by Mary Ellen Bowden.’

96 From my survey of traditional and Renaissance astrology (Clulee, ‘ “The Glas of Creation”,’ pp. 97-104), it appears that these sources did not provide the essential basis for Dee's theory.

97 Dee, in Corpus Christi College MS. 191 [1556], lists two copies of Euclid's Optics (fols. 78, 79); four copies of the medieval Latin Pseudo-Euclid, De Speculis or Catoptrica (fols. 77^v, 79, 81, 83); al-Kindfs De radiis (fol. 81) and De umbris et causis diversitatis aspectuutn (fol. 81); Robert Grosseteste's De impressionibus aeris (fol. 79^v), De iride (fol. 79), and De luce, colore, et frigide (fol. 82^v); Roger Bacon's De multiplicatione speciemm (fol. 79), two copies of his Perspectiva (fols. 77^v, 79), and the following works in which optics plays a major role in natural philosophy: Magnum opus communium naturalium (fol. 79) and Summa ad Clementum [Opus majus] (fol. 83^v). In addition, Dee acquired at this time a collection of the Opus majus, Opus minus, and Opus tertium (British Museum Ms. Cotton Tiberius c.v.), and another collection with the titles Compendium philosophiae, De corporibus coelestibus, and De mathematica (Bodleian Library Ms. Digby 76). In Corpus Christi College MS. 191, Dee also lists four copies of Alhazen, Perspectiva (fols. 78^v, 79); two copies of Witelo, Perspectiva (fols. 80, 82^v); two copies of Pecham, Perspectiva communis (fols. 78, 81^v); a copy of Pisanus [sic, Pecham?], Perspectiva communis (fol. 81); a commentary on that by Domenico de Hassia [sic, Henry of Hesse/Henry of Langenstein] (fol. 81); an anonymous Questiones super perspectivam (fol. 81^v); and three treatises on burning mirrors (fols. 78^v, 82^v).

98 Calder, I, 515-522. Calder has emphasized that this treatise by al-Kindī was an important source of Dee's ideas. The treatise was also known as the Theoreica artium magicarum and has never been published. I have used the thirteenth-century English manuscript, Oxford, Bodleian Library MS. Selden Supra 76, fols. 47-60^v. Dee borrowed this in 1556, according to the Corpus Christi College MS. 191, fol. 81. There are recent discussions of al-Kindī's De radiis in Graziella Federici-Vescovini, Studi sulla prospettiva medievale, Università di Torino Pubblicazioni della Facoltà di Lettere e Filosofia, XVI, 1 (Turin: G. Giappichelli, 1965), pp. 44-47; and in Lindberg, David C., Theories of Vision from al- Kindī to Kepler (Chicago: University of Chicago Press, 1976), p. 19 Google Scholar.

The similarity between al-Kindī's ideas and some of Dee's aphorisms is very close and in some cases Dee even takes verbal formulae from al-Kindī. Cf. the following: al-Kindī, De radiis stellarum, Bodleian MS. Selden Supra 76, fols. 49v-5o: ‘Hoc igitur per vera assumentes divina quod omne quod actualem habet existentiam in mundo elementorum radios emittit in omnem partem qui totum mundum elementorum replent suo modo unum est quod omnis. unde est quod omnis locus huius mundi radios continet omnium rerum in ea actu existentium, et sicut unaquaque res differt ab alia sic radii uniuscuiusque differunt in effectu et natura a radiis omnium rerum aliarum … ,’ with P.A., IIII, VI, and VII; and al-Kindī, De radiis … , Bodleian MS. Selden Supra 76, fol. 49: ‘Diversitas igitur rerum in mundo elementorum apparens in quocunque tempore ex duabus praecipue causis percedit. scilicet, ex materiarum diversitate et varia stellarium radiorum operatione,’ with P.A., CXIII.

99 Al-Kindī, De radiis, Bodleian MS. Selden Supra 76, fols. 48-49: ‘Omnis enim Stella suam habet propriam naturam et conditionem in qua radiorum proiectio cum aliis continetur et sicut unaquaeque suam habet propriam naturam et conditionem quam totaliter in nulla alia contingit reperire in qua radiorum emissio continetur. Sic ipsi radii in diversis stellis sunt diversae naturae sicut et ipsae stellae sunt in natura diversae… . In omnem enim locum omnis Stella radios effundit, propter quod radiorum diversitas quasi in unam conflata variat omnium contenta locorum cum in omni loco diverso diversus sit tenor radiorum qui a totali stellarum armonia [sic] derivatur… . Liquet igitur quod omnia loca diversa et omnia tempora diversa diversa constituunt individua in hoc mundo quod facit coelestis armonia [sic] per radios in mundum proiectos sese continue diversificans.’ See also the passages cited in n. 98 above.

100 ibid., fols. 48, 49^V.-50: ‘Nam radius qui a centro stellae ad centrum terrae descendit fortissimus esse probatur in operationibus suae speciei. Qui autem a centro terrae obliquantur secundum proportionem obliquationis in effectu debilitatur, nisi in quantum aliarum stellarum radiis concurrentibus in eisdem locis confortantur.’

101 Al-Kindī was also interested in optics, which is the likely basis for his notion that astral influences behave as light rays. There appears to have been little communication, however, between his optics, which is purely mathematical and does not indicate an interest in astrology, and the theory in the De radiis. An explicit connection of mathematical optics and astrology had not, therefore, been made.

102 Al-Kindī, De radiis, Bodleian MS. Selden Supra 76, fols. 47^v-48.

103 These were Grosseteste's De impressionibus aeris, De iride, and De luce, colore, et frigide; see above n. 97. Thus, Dee had no direct access at this point to the works in which Grosseteste developed an Augustinian and Neoplatonic epistemology that emphasized the superiority of divine illumination over empirical knowledge, to the effect that a priori principles and deductive reasoning play a predominant role in Grosseteste's natural philosophy. See Eastwood, ‘Medieval Empiricism,’ p. 309; and Bruce S. Eastwood, ‘Grosseteste's “Quantitative” Law of Refraction: A Chapter in the History of Nonexperimental Science,’ Journal of the History of Ideas, 28 (1967), 409.

104 Grosseteste's natural philosophy has been considered an example of a highly Neoplatonic ‘light metaphysics'; see Crombie, p. 109; Eastwood, ‘Medieval Empiricism,’ p. 308; and Eastwood, Bruce S., ‘Metaphysical Derivations of a Law of Refraction: Damianos and Grosseteste,’ Archive for History of Exact Sciences, 6 (1970), 232 CrossRefGoogle ScholarPubMed. While Grosseteste does appeal to certain metaphysical principles—e.g., the uniformity and economy of nature (Eastwood, ‘Grosseteste's “Quantitative” Law of Refraction,’ pp. 409, 412-413)— the role played by light in Grosseteste's natural philosophy is that of a physical agent that provides a mechanics describing the behavior of the forms and virtues of heaven and earth; see Aleksander Birkenmajer, ‘Études sur Witelo, II—III,* Bulletin international de l'Académie polonaise des sciences et lettres (Cracow, 1920), p. 356. It is this sense that seems most to have influenced Dee.

105 Robert Grosseteste, De luce seu de inchoatione formarum, in Robert Grosseteste, Die philosophischen Wake des Robert Grosseteste, ed. Ludwig Baur, Beiträge zur Geschichte der Philosophie des Mittelalters, 9 (1912), pp. 51-52. This has been translated by Riedl, Clare C. as Grosseteste, Robert, On Light (Milwaukee: Marquette University Press, 1942)Google Scholar.

106 Crombie, p. 106.

107 Grosseteste, De luce, pp. 52-57.

108 Crombie, pp. 59-60; Eastwood, ‘Metaphysical Derivations,’ p. 235.

109 Eastwood, ‘Metaphysical Derivations,’ pp. 307-308.

110 Crombie, p. 91.

111 Robert Grosseteste, De lineis, angulis et figuris, in Die philosophischen Werke, pp. 59-60. Crombie, pp. 104-106. Ludwig Baur, Die Philosophie des Robert Grosseteste, Bichofs von Lincoln, Beiträge zur Geschichte der Philosophie des Mittelalters, 18, Heft 4-6 (1917), pp. 92-93.

112 Grosseteste, De lineis, pp. 60-61. Robert Grosseteste, De impressionibus elementorum, in Die philosophischen Werke, p. 87.

113 Robert Grosseteste, De impressionibus aeris (de prognostication), in Die philosophischen Werke, pp. 48-49. Grosseteste, De lineis, pp. 61-65.

114 Bacon, Roger, The Opus Majus, tr. Robert Belle Burke, 2 vols. (New York: Russell & Russell, 1962), 1, 116, 120 Google Scholar. Similar treatments of these subjects are also given by Roger Bacon in his Opus tertium, in Roger Bacon, Opera quaedam hactenus inedita, ed. J. S. Brewer (London: Longman, Green, Longman, and Roberts, 1859); and in his Liber primus communium naturalium, in Bacon, Roger, Opera hactenus inedita Rogeri Baconi, ed. Robert Steele (Oxford: Clarendon Press, 1909-40)Google Scholar, fasc. II. Among the manuscripts listed in the 1556 catalogue, Dee includes several of these works, see above, n. 97.

115 Bacon, The Opus Majus, 1, 130. Cf. Roger Bacon, De multiplicatione specierum, in Bacon, Roger, The Opus Majus of Roger Bacon, ed. J. H. Bridges, 2 vols. (Oxford: Clarendon Press, 1897), II, 407–413 Google Scholar. Crombie, Robert Grosseteste, p. 144. Bacon was also clearly familiar with the optics of al-Kindī: see Bacon, De multiplicatione specierum, pp. 494-496; and Easton, Stewart C., Roger Bacon and His Search for a Universal Science (New York: Columbia University Press, 1952), p. 104 Google Scholar.

116 Bacon, The Opus Majus, tr. Burke, I, 131-133. Cf. Bacon, De multiplicatione specierum, pp. 457-460. See also Vescovini, Studi, pp. 57-62.

117 Bacon, The Opus Majus, tr. Burke, I, 138. Cf. Bacon, De multiplicatione specierum, pp. 458-460, 539.

118 Bacon, The Opus Majus, 1, 128-129.

119 Ibid., 1, 139-140. Cf. Bacon, De multiplicatione specierum, pp. 518-519, 534-541.

120 In the 1556 lists of manuscripts, Dee cites Ibn al-Haytham's Perspectiva: see above, n. 97, under Alhazen. Ibn al-Haytham's Perspectiua was published in the sixteenth century as the Opticae thesaurus Alhazeni, ed. P. Risner (Basel, 1572), and has recently been reprinted (New York: Johnson Reprint Corp., 1972).

121 Lindberg, ‘Introduction,'JohnPecham, pp. 24-25. Roshdi Rashed, ‘Le “Discourse de la Lumière” d'Ibn al-Haytham,’ Revue d'histoire des sciences et de leurs applications, 21 (1968), 211-213.

122 Lindberg, ‘Introduction, ‘John Pecham, pp. 25-27. The question of influences among Bacon, Witelo, and Pecham has been treated extensively in Lindberg, David C., ‘Lines of Influence in Thirteenth Century Optics: Bacon, Witelo, and Pecham,’ Speculum, 46 (1971), 66–83 CrossRefGoogle ScholarPubMed.

123 Witelo, Perspectiva, ed. F. Risner (Basel, 1572: rpt. New York: Johnson Reprint Corp., 1972), p. 103. Birkenmajer, ‘Études sur Witelo, II—III’ (1920), p. 356.

124 John Pecham, Perspectiva communis, Bk. II, prop. 56, in John Pecham, pp. 210-211. Crombie, Robert Grosseteste, p. 165. In his 1556 list of manuscripts, Dee lists several copies of Witelo's Perspectiva and Pecham's Perspectiva communis: see above, n. 97.

125 Crombie, pp. 165, 213-214. Lindberg, ‘Introduction,’ John Pecham, pp. 29-32.

126 Vescovini, Studi, pp. 204, 240, points out that the natural philosophy characteristic of al-Kindī, Grosseteste, and Bacon was no longer associated with the study of optics by fourteenth- and fifteenth-century writers.

127 Calder, II, 254, n. 237, emphasizes the dependence of the Propaedeumata on Roger Bacon and mentions that Richard Burton, in The Anatomy of Melancholy, remarked that it is based on Bacon's De multiplication specierum.

128 ‘Speculum unitatis: sive Apologia pro Fratre Rogerio Bachone Anglo in quo docetur, nihil ilium per Daemoniorum auxilia fecisse, sed Philosophum fuisse maximum: naturaliterque, & modis homini Christiano Ileitis, maximas fecisse res: quas, indoctum solet vulgus in Daemoniorum referre facinora.’ Dee's concern was not misplaced. Molland, A. G., ‘Roger Bacon as Magician,’ Traditio, 30 (1974), 445–447 CrossRefGoogle Scholar, points out that there was a legendary tradition about Bacon as a magician and that John Bale, in his Summarium of 1548, described Bacon as a ‘juggler and necromantic mage,’ who was said to have performed great marvels ‘not by the power of God but by the operation of evil spirits.'Whether Dee's defense did any good or not is difficult to determine, but Dee was not alone in finding Bacon a hero of science, for the same Bale, in his Catalogus of 1557-59, said of Bacon that ‘he was possessed of incredible skill in mathematics and devoid of necromancy, although many have slandered him with it’ (Molland, p. 448). The similarities between Bale's judgments and Dee's concern are interesting, but I have found nothing that would indicate any connection between the two men at this time.

129 Dee's edition was not published until 1618.1 have used the reprint found in Bibliotheca chemica curiosa, ed. Johannes Jacobus Manget, 2 vols. (Geneva, 1702), 1, 616-626. Calder, 1, 458, 494; II, 238, nn. 171-174, and 391, n. 27, discusses this work with regard to natural magic and stresses its importance for Dee and his optical magic in particular.

130 Bacon, Epistola de secretis operibus, in Bibliotheca chemica curiosa, 1, 616-618.

131 Ibid., 1, 620. Cf. Bacon, The Opus Majus, tr. Burke, I, 133. See also Molland, pp. 452-458.

132 See Dee's notes to ch. IX of Bacon, Epistola de secretis operibus, I, 626. This note is an almost exact quote from Bacon, Opus tertium, Opera quaedam hactenus inedita, pp. 39-40.

133 Bacon, Opus tertium, pp. 39-42. See also Bacon, Opus minus, in Bacon, Opera quaedam hactenus inedita, p. 359.

134 Bacon, Opus tertium, p. 40.

135 This idea was reinforced by another source of Dee's optical astrology, al-Kindī's De radiis, MS. Selden Supra 76, fols. 53-54, 58^v-59.

136 The legend on the title page indicates that the Monad contains all of the planets and all that wise men seek. See also, P.A., X, XI, XII.

137 Bacon, The Opus Majus, ed. Burke, 1, 134-135.

138 John Dee, De speculis comburentibus libri 5. Inventa Joannis Dee londinensis, circa illam coni recti atque rectanguli sectionem quae ab antiquis mathematicis parabola appellabatur, Martij 8. 1558, British Museum MS. Cotton Vitellius C.VII., fols. 279-308.

139 Calder, I, 460-461. On Anthemius, see Heath, Thomas L., ‘The Fragment of Anthemius on Burning Mirrors and the “Fragmentum mathematicum Bobiensis”,’ Bibliotheca Mathematica, 3rd ser., 7 (1907), 225-33Google Scholar. For Ibn al-Haytham, see Wiedemann, Eilhard, ‘Zur Geschichte der Brennspiegel,’ Annalen der Physik and Chemie, N.S. 39 (1890), 110–130 CrossRefGoogle Scholar; Heiberg, J. L. and Wiedemann, Eilhard, ‘Ibn al Haitams Schrift über parabolische Hohlspiegel,’ Bibliotheca Mathematica, 3rd ser., 10 (1910), 201–237 Google Scholar; and H. J. J. Winter and W. ‘Arafat, ‘Ibn al-Haitham on the Paraboloidal Focussing Mirror,’ Journal of the Royal Asiatic Society of Bengal, 3rd ser., 15, nos. 1-2 (1949), 25-40. On Ibn al-Haytham in general, see Sabra, A. I., ‘Ibn al-Haytham,’ in Dictionary of Scientific Biography, ed. Charles Coulston Gillispie (New York: Charles Scribner's Sons, 1970-), VI, 189–210 Google Scholar. Among the numerous optical works listed by Dee in his 1556 manuscript lists are several works dealing specifically with burning mirrors: see above, n. 97. Dee may very well be repeating a solution that he found in one of these works.

140 It should be stressed that John Dee was a good mathematician, a point that has been neglected by those who have emphasized the Hermetic and occult aspects of his work. It is unfortunate that Dee's work in mathematics has not received careful study from historians of mathematics, although some of the dimensions of Dee's serious mathematical work and contacts have been explored. See for example Rosen, Edward, ‘Dee and Commandino,’ Scripta Mathematica, 28 (1970), 321–326 Google Scholar; Rose, Paul Lawrence, ‘Commandino, John Dee, and the De Superficierum Divisionibus of Machometus Bagdedinus,’ Isis, 63 (1972), 88–93 CrossRefGoogle Scholar; and Watson, Andrew G., ‘The Provenance of John Dee's Manuscript of the De Superficierum Divisionibus of Machometus Bagdedinus,’ Isis, 64 (1973), 382–383 CrossRefGoogle Scholar; in addition to the older works by E. G. R. Taylor on Tudor and Stewart navigation, which include material on Dee's contributions to these fields.

141 See also Dee, Mathematicall Praeface, sig. biiij.

142 “Tu ergo qui NATURAE observantissimus esse Cultor soles: NATURAE, in istis Aphorismis, scrutare virtutes veras, virtutes magnas, virtutes paucis vix credibilis Sapien tibus, at paucissimis notas.’ See also Dee, Mathematical! Praeface, sigs. biij^v-biiij: ‘In my Propaedeumes (besides other matter there disclosed) I have Mathematically furnished up the whole Method: to this our age, not so carefully handled by any, that ever I saw, or heard of.'

143 Steenberghen, Fernand van, La Philosophic au XIII^e siecle (Louvain: Publications Universitaires, 1966)Google Scholar, ch. IV. LefF, Gordon, Paris and Oxford Universities in the Thirteenth and Fourteenth Centuries (New York: John Wiley & Sons, 1968), pp. 210–211 Google Scholar. There are a number of respects in which the philosophy of Thomas Aquinas exhibits Neoplatonic elements, although there is no firm consensus on this issue yet. See Henle, R. J., Saint Thomas and Platonism (1954; rpt. The Hague: Martinus Nijhoff, 1970), pp. xvii–xx Google Scholar; Kristeller, Paul O., Medieval Aspects of Renaissance Learning, ed. and tr. Edward P. Mahoney (Durham, N.C.: Duke University Press, 1974), pp. 33–34 Google Scholar, 36, and 75-77. With regard to Dee's specific sources, Roger Bacon's philosophy may reflect Neoplatonic influences but Bacon was not consciously Platonic or Neoplatonic. He began his career as an arts professor at Paris as a teacher of Aristotle and constantly strove to save the letter of Aristotle while reconciling him with his religious beliefs; so it is difficult to call him a Platonist (Easton, p. 56; Nicholas W. Fisher and Sabatai Unguru, ‘Experimental Science and Mathematics in Roger Bacon's Thought,’ Traditio, 27 [1971], 375). The same conclusion applies to Dee in 1558. His sources were largely Aristotelian and, although some of these contained Neoplatonic elements that carried over into Dee's philosophy, he did not assume a consciously Neoplatonic position in contrast to his earlier Aristotelian training.

144 Garin, ‘Magic and Astrology,’ pp. 148-154; Yates, Giordano Bruno, pp. 17-18, 48-49, 58; and Burke, John G., ‘Hermeticism as a Renaissance World-View,’ in Robert S. Kinsman, ed., The Darker Vision of the Renaissance, UCLA Center for Medieval and Renaissance Studies, Contributions, 6 (Berkeley: University of California Press, 1974), pp. 95–96 Google Scholar.

145 Pomponazzi, De naturalium effectuum admirandorum causis, seu de incantationibus, pp. 98, 105-106. Cf. Giovanni Pico della Mirandola, Condusiones magiae … secundum opinionem propriam, in Giovanni Pico della Mirandola, Condusiones sive theses DCCC Romae anno i486 publice disputandae, sed non admissae, ed. Bohdan Kieszkowski (Geneva: Librairie Droz, 1973), pp. 78-79.

146 Molland, p. 445, also makes this point for Renaissance magical writers in general, noting that medieval sources of Renaissance magic included Roger Bacon, al-Kindī, William of Auvergne, and Albertus Magnus in addition to prisca magia.

147 French, John Dee, pp. 93-96.

148 Calder, II, 5-7.

149 In subsequent studies I hope to explore some of these new interests and their role in the development of Dee's thought.