Abstract
In one of the final scholarly works of her long, productive and distinguished career, Germana Ernst has produced a beautiful and useful critical edition of Galileo’s astrological manuscript 81, entitled “Astrologica Nonnulla,” held by the Biblioteca Nazionale Centrale in Florence. It contains horoscopes for 19 people (some with two slightly different figures) in Galileo’s own hand and was gathered together into one manuscript from originally separated folia. Although it has been known for over a century (since 1881 when Antonio Favaro wrote about it in a very brief article 1 ) and although its attribution has never been seriously challenged, MS Gal. 81 and the essentially normal astrological practices that it reveals have not yet been taken fully into account in the literature seeking to understand and assess Galileo’s life and works, and it has never been published in its entirety. This desideratum has now been admirably fulfilled in Ernst’s edition that appears on pages 103–193 of Appendix III to Galileo’s multi-volume and indispensible Opere. 2
While teaching at the University of Padua, Galileo practised astrology by constructing and interpreting horoscopes for a range of patrons, students and family members, seeking, among other things, to raise extra money as we can see in his contemporary account books for payments made to him “per sortem.” This evidence dates some of these horoscopes to 1603, that is, soon after the death of one of his early patrons, Gian Vincenzo Pinelli (1535–1601), one of the great understudied figures in Galileo’s early orbit. Other of these horoscopes were made soon after the births of his two daughters, Virginia (12 August 1600) and Livia (18 August 1601), which might also explain the need for extra money.
We possess other evidence for Galileo’s astrological practice around this time, including his first investigation by the Venetian Inquisition in 1604, following the official denunciation made by his former amenuensis, Silvestro Pagnoni from Pesaro, who had accused Galileo of practising a deterministic astrology. We know about this revealing incident in some detail from Antonino Poppi’s valuable researches, including that the case was dropped because Galileo was practising normal, not deterministic astrology. As we now know without any doubt, throughout the 16th and well into the 17th century astrology was still taught at the finest Italian universities, including at both Padua and Bologna, and was a normal part of the study, practice and teaching of an early modern “mathematicus.” We can also tell this from the extant manuscript of a course of 113 lectures on Ptolemy’s Tetrabiblos composed and taught at the University of Pisa by Giuliano Ristori (d. 1556) in the 1540s, and revised and reused by Filippo Fantoni (ca. 1530–91) in the 1580s, while Galileo was a student there, although we do not know whether he actually took Fantoni’s course. 3
Ernst’s edition begins with an all-too-brief introduction, in which she discusses some of these and other relevant issues, including a concise description of how Galileo made these horoscopes and her identification of the ephemerides he used (pp. 103–7). In the body of her edition, she clearly sets out the particulars of each horoscope, including the numerical astrological and astronomical details in Galileo’s worksheets (some quite extensive) that were used towards an interpretation or judgement, five of which are appended to their respective horoscopes. Planetary dignities and debilities with their numerical assessments loom large on these pages, especially in his friend and patron, Gianfrancesco Sagredo’s (1571–1620) horoscope, as do tables with ephemeris entries for the day in question, along with the calculations that Galileo employed to determine planetary locations. Ernst has also supplied the horoscopes with numerous relevant explanatory annotations.
Most of the people for whom horoscopes were constructed in MS 81 can be identified. Some were family members, including Galileo’s sister, Virginia; his brother, Michelangelo; his nephew, Cesare Galletti; and his daughters, Virginia and Livia. In her presentation of this material, Ernst has usefully rearranged the horoscopes, which were randomly compiled in the manuscript, into five groups: five horoscopes of family members, two horoscopes for himself, an extensive horoscope for Sagredo with numerous tables, three for his students in Padua, and nine for various other people, including three who are unidentified.
In addition to setting out all of the astronomical and astrological data as well as the numerical calculations used in MS 81 for erecting and interpreting these horoscopes, perhaps the most valuable feature of Ernst’s edition is the transcription of Galileo’s astrological interpretations, which were all written in Latin in the five horoscopes that include them, some of which are very difficult to read in the manuscript. These interpretations are very interesting, in that we can thereby catch a glimpse of Galileo doing the normal work of both casting and interpreting horoscopes. We have interpretations for the extensive horoscope Galileo made for Sagredo (p. 126), but also for his two daughters, Virginia and Livia (pp. 118, 120), and for his nephew, Cesare Galletti (p. 113). The longest one by far is for his student, Cristoforo Stettner, which systematically discusses the different parts of his life, including marriage, sicknesses and death (pp. 128–9). The construction of his own horoscope (in two variant versions, but without an interpretation) and those for his two daughters (with their interpretations), as well as for other family members, belie assertions claiming that Galileo himself personally rejected astrology or that he only used it cynically for patronage purposes. None of the horoscopes in MS 81 are elaborate presentation copies, however, nor do I know of any that exist. Rather, they are the working papers of a normal astrologer practising in the early 17th century.
After the edition of the horoscopes (pp. 111–35), there follow two appendices. The first provides a critical edition of Galileo’s geniture for Cosimo II de’ Medici (p. 136), for which she also reproduces in facsimile the two manuscript images of this horoscope in MS Gal. 48 (pp. 188–9) that Galileo had used for composing the astrological dedicatory preface to the Sidereus Nuncius. One of these has Galileo’s wash drawing of a telescopic observation of the moon. The second appendix presents four other natal horoscopes for Galileo, but not drawn up by him, from other manuscript geniture collections (pp. 137–9; facsimiles at 190–3). These include three from Florence and a fourth from Rome, found, curiously, among the extensive material, astrological and otherwise, collected at Santa Prassede in 1630 during the investigation of Orazio Morandi and his extraordinary astrologico-political think tank in Urban VIII’s Rome. This took place within the complex and colourful context of the publication of Galileo’s Dialogue.
The edition concludes with an apparatus compiled by Olivia Catanorchi that includes a key to identifying the astrological symbolism in MS Gal. 81 (p. 140) and the abbreviations that Galileo used (p. 141), as well as a list of all the fixed stars and constellations (both zodiacal and extra-zodiacal) appearing in MS 81 (pp. 142–5). The last entry is a glossary of technical terms (pp. 146–9). The edition is completed by sharp and clear photographic reproductions in facsimile of all of MS 81’s relevant folia – excluding blank pages, and material that is certainly not in Galileo’s hand or is otherwise insignificant (pp. 151–87) – in addition to the horoscopes made for Cosimo II in MS 48 (pp. 188–9) and the other horoscopes of Galileo’s nativity (pp. 190–3).
Almost 150 years after Favaro’s brief treatment, Germana Ernst’s valuable critical edition of Galileo’s astrological manuscript may now be used as a solid foundation on which to base a comprehensive study of the technical and interpretive features of Galileo’s astrological practice. As it turns out, MS Gal. 81 only collects nativities or birth horoscopes, the only astrological practice by Galileo for which we have evidence. Within these natal horoscopes, there is apparently nothing new and/or revolutionary, thus revealing a traditional astrological practitioner. Furthermore, his use of Arabic techniques for determining the length of life with the “hylec” and “alcocoden” as well as his use of directions and numerous astrological dignities and debilities indicates his use of traditional medieval Arabic and Latin astrological techniques – as we can clearly see in the numerous tables and interpretations in the horoscopes – fully a century after Giovanni Pico della Mirandola had attacked these and other techniques in his Disputations against Divinatory Astrology (1496). 4 The inescabable fact – known for some time now – is that this “father of modern science” was also a practising astrologer, a normal part of the practice and teaching of an early modern “mathematicus.” Germana Ernst has now provided the scholarly community with a very useful working edition of this central source for (but by no means all of the evidence for) understanding, interpreting and assessing astrology’s several roles in Galileo’s life and work.