Late 15th Century
Medieval and Early Modern manuscripts
Gerardus Feltrensis, Summa de astris, Parts I-II only, written in a cursive humanistic hand and illustrated with pen-drawn astronomical diagrams in northern Italy (Veneto?) in the late 15th century.
Gerardus compiled the Summa about 1263-68 and dedicated it to the General of the Dominican order John of Vercelli (1264-1283). Naming Ptolemy, Albumasar, Alfargani, Omar, Zahel and Masshallah as his sources, he divided the text into three parts: in Part I he described astronomy; he dedicated Part II to astrology; in Part III he highlighted the differences between the two disciplines in order to refute judicial astrology on theological and philosophical grounds.
In the 15th century the text was studied by Pico della Mirandola and influenced the work of Marsilio Ficino. It was never published in print, though, and is now known from five manuscripts, including the present one. The four other manuscripts are as follows: Bologna, Biblioteca Comunale dell'Archiginnasio, MS. A. 539, 1r-95r, second half of the 13th century; Milan, Biblioteca Ambrosiana, MS. C 245 Inf., end of 13th century; Poland, Kraków, Biblioteka Jagielloska, MS. 610, 15th century; Vatican City, Biblioteca Apostolica Vaticana, MS. Pal. Lat. 1388, ff. 37r-110r, 15th century.
The present manuscript only includes the preface (ff. 1r-2v), Part I (ff. 3v-66v) and Part II (ff. 67r-115v), each part preceded by an index (ff. 2v-3r, 66v). The dates given as chronological examples at the beginning of the text and for the passage of a comet differ from those given in the other manuscripts: '
Anno domini 1263 tercia die intrante nouembri
Anno domini 1268 28 die Augusti
Anno domini 1265. 12a die octobris
Anno domini 1266 prima die octobris
' (f. 4r); 'Ego autem cum multis aliis anno ab incarnatione domini 1268 in Lombardia vidi cometem' (f. 65r: the comet is attested here in 1268 instead of 1264). For the other manuscripts, see Thorndike, Latin Treatises on Comets, pp. 185-195, in particular p. 193; Zambelli, The 'Speculum astronomiae' and its Enigma, chapter 6, 'Astrology in the Early Dominican School and Gerard of Feltre', pp. 153, 158-159.
f. 11r Incipit: [I]ESU*CrISTI*GRATIA*PREVE/niente ac subsequente summa hec de / astris compilata et scripta est, ex dictis / Ptolomei. Albumasar. Alfragani. Alca/bicii. Oamar. Zahel et Masala qui fuerunt / Auctores et magistri astrorum ...
f. 115v Explicit: ... Ad cognoscendum assumpta/Arbitrentur./ LAVS DEO.