Andalus de Nigro (1270-1342).
Opus astrolabii. Ed. Petrus Bonus Advogarius. Ferrara, Johann Picardus, de Hamell, 8 July 1475.
Small folio (281x218 mm). Collation: [1-210]. 19 of  leaves, lacking the last blank leaf. Text in one column, 40 lines. Type: 1:101G. The first page decorated with a five line vinestem initial 'S', illuminated in red and blue on a silver background with extension in half of the margin; sixty-nine three-line initials alternately in red or blue, rubricated throughout. Eighteenth-century speckled boards, possibly recased. A tall copy, still attractive in spite of a waterstain in the lower right corner, heavier on the last quire, not affecting the text apart from the last two leaves. On fol. /8v one initial was lost and a few words of lines of text retouched in ink. A portion of the right side of the last leaf was missing and skilfully laid on an ancient leaf; along the right side some words of twenty-one lines neatly supplied in brown ink. Some other waterstains or spots, old repairs to the penultimate leaf.
One of the earliest printed astronomical texts, and one of the rarest scientific incunables to have appeared in Ferrara: the first and only edition of the Opus astrolabii, here exceptionally presented in the unique copy known with an illuminated initial. Only ten copies of this Ferrarese edition – a landmark in the history of astronomy, especially in the theorica planetarum – are recorded among the institutional libraries (four in Italy and two in the United States).
The famous astronomer and traveller from Genoa Andalo de Nigro succeeded Cecco d'Ascoli to the chair in Florence, and, in about 1330, became the teacher of Giovanni Boccaccio. Geoffrey Chaucer (who, some seventy years later, wrote the first work in English on a scientific instrument – the Treatise on the Astrolabe – and was inspired by Boccaccio for his Tales) may have known Andalo's Opus astrolabii through either the Genealogiae Deorum, which first appeared in 1472 (see no. 16) or the De casibus virorum illustrium, printed in 1474-1475. In the latter, Boccaccio calls Andalo a 'venerable' man, and compliments him on his vast knowledge of the stars, gained 'by direct vision' during his travels around the world; indeed, in 1314, the Genoese was appointed Ambassador to the Emperor of Trebisonda (Trabzon), and Giovanni Battista Ramusio – in his preface to the Viaggi di Messer Marco Polo (which opens the second volume of his Navigationi et viaggi of 1559) – identified Andalo, instead of the Pisan Rustichello, as the prisoner to whom Marco Polo dictated his memoirs.
Andalo's treatise describes the use and construction of the astrolabe, an instrument indispensable for compiling astronomical tables and for solving computational problems in spherical astronomy as well as in astrological predictions. The work also exerted great influence upon Western medicine, with Andalo being considered a theorist of astrological medicine, a discipline which claims to use the study of planetary positions to predict whether a patient would recover or to determine the best times for bleeding or operating.
The Opus astrolabii was edited by the physician and astrologer Pietro Bono Avogario (d. 1506), active – as the colophon states – 'in foelici gymnasio ferrariensi', and was printed by the Frenchman Jean Picard de Hamell who “is not known to have issued at Ferrara any book besides the Nigro” (BMC vi, 608).
HR 967; BMC VI, 608; IGI 456; Goff A-573; Lalande 12; Sarton III, 647; Stillwell, Awakening, 808; Thorndike IV, 465; A. M. Cesari, “Theorica planetarum di Andalò Di Negro. Questioni di astronomia. Indagine delle fonti astronomiche nelle opere del Boccaccio. Edizione critica”, Physis, 27 (1985), pp. 181-235; D. Blume, “Andalo di Negro und Giovanni Boccaccio: Astrologue und Mythos am Hof des Robert von Anjou”, T. Michalsky (ed.), Medien der Macht. Kunst der Anjous in Italien, Berlin 2001, pp. 319-335; Philobiblon, One Thousand Years of Bibliophily, no. 18.