The Origins of the “Theorica Planetarum”

There is no reason here to give specific references to well-known translations. The reader will find ample information in such standard works as Carmody F. J. , Arabic astronomical and astrological sciences in Latin translation (Berkeley and Los Angeles, 1956), supplemented by Sarton's G. Introduction to the history of science, i-iii (Baltimore, 1927–48), and Thorndike L. and Kibre P. , Catalogue of incipits of mediaeval scientific writings in Latin (2nd ed., London, 1963).

Edited in Curtze M. , Petri Philomeni de Dacia in Algorismum vulgarem Johannis de Sacrobosco Commentarius una cum Algorismo ipso (umptibus Soc. Reg. Scientiarum, Hauniae (Copenhagen), 1897).

There is no modern edition of the Compotus. It was first published by Melanchthon at Wittenberg, 1545.

Thorndike L. , The Sphere of Sacrobosco and its commentators (Chicago, 1949).

The development of the Corpus is described in greater detail in Pedersen O. , “The Corpus astronomicum and the traditions of medieval latin astronomy”, Studia Copernicana, xiii (Warsaw, 1975), 57–96.

The most complete and important among the commentaries was written in a.d. 1318 by de Parma Thadeo . It seems to have been a set book in the Medical Faculty at Bologna during the fourteenth century.

Among the revised versions must be mentioned the Theorica by the fourteenth-century Oxford astronomer Brytte Walter , which shows some influence from the Merton School of mathematics. It is often confused with the original text because of its similar incipit: Circulus eccentricus et egresse cuspidis et egredientis centri idem sunt. Among the MSS are Egerton 847 and 889, Bodl. 300, Digby 15, 48, 93 and 98, and Wood D.8.

For this episode and its bearing upon the question of the Humanist influence on Renaissance astronomy, see Pedersen O. , “The decline and fall of the Theorica planetarum”, Studia Copernicana, xvi (Warsaw, 1978), 157–85.

The Theorica was printed at Ferrara , 1472; at Bologna , 1477, 1480; and at Venice , 1478 (twice), 1518 (twice) and 1531.

These headings are taken from the MS Paris, Bibl. Nat. Lat. f. 222r; it has a separate table of contents beginning Theorica planetarum habet octo capitula. The purely astronomical aspects of the text can be studied in the English translation in Grant E. (ed.), A source book in medieval science (Cambridge, Mass., 1974), 451–64.

This method was first correctly described by Petersen Viggo M. , “The three lunar models of Ptolemy”, Centaurus, xiv (1969), 142–71.

On the history of the term aux see Nallino C. A. , Raccolti di Scritti, v (Rome, 1944), 307, n. 1; on genzahar see Hartner W. in Oriens-occidens (Hildesheim, 1968), 264.

See Pedersen O. , “A fifteenth century glossary of astronomical terms”, Classica et mediaevalia, Dissertationes IX (F. Blatt dedicata) (Copenhagen, 1973), 584–94, which contains an edition of the astronomical dictionary found in the MS 155, ff. 41r–42r, in St John's College, Cambridge.

See Pedersen O. , A survey of the Almagest (Odense, 1974), 343f.

An exception was Brytte Walter who clearly stated the correct condition for a stationary point.

See the Novae theoricae planetarum (Augsburg (Ratdolt), 1482), ff. 88r seq., in particular the figure on f. 88v.

See the Augsburg edition of the Disputationes, ff. 65v seq., printed with the edition of Novae theoricae planetarum cited in ref. 16.

Ibid., f. 60v.

Boncompagni B. , “Delia vita e delle opere di Gherardo da Sabbionetta”, Atti dell'Accademia Pontificia de'Nuovi Lincei, iv, 1850–51 (Rome, 1852), 449–93. The list in question was edited by Sudhoff K. , “Die kurze ‘Vita’ und das Verzeichnis der Arbeiten Gerhards von Cremona”, Archiv für Geschichte der Medizin, viii (1914), 73–82.

Sarton , Introduction, ii, 987; the prognostications are found in the MSS Vat. Lat. 4083, ff. 3r–37r, and Vienna VIN 4997, ff. 1r–85r.

Duhem P. , Le système du monde, iii (Paris, 1915), 319 seq.

See Nallino , Raccolti di Scritti, v, 304 seq.

Thorndike , The Sphere of Sacrobosco, 35 seq. and 463–75.

Pedersen O. , “The Theorica planetarum-litemture of the Middle Ages”, Classica et mediaevalia, xxiii (1962), 225–32.

Quoted from the Florence MS Plut. 29,7, f. 110v.

University Library Basel, MS F.III.25, f. 18v.

University Library Utrecht, MS 1.M.1, f. 31r.

Cambridge University Library, MS Kk.1.1, ff. 192r–210v.

Lemay R. , “Gerard of Cremona”, Dictionary of scientific biography, xv (New York, 1978), 173–92, in particular p. 189.

Kiseleva L. I. , Latinskie Rukopisi Biblioteki Akademii Nauk USSR (Leningrad, 1978), 117–21. Here the manuscript of the Theorica is described as two separate treatises, viz. a Theorica planetarum on ff. 13v–15v of the codex F.8 and a De latitudinibus planetarum on ff. 16v–17r. Chap. 8 is missing. I am indebted to Mr S. Balle for a translation of the relevant pages of the catalogue.

I wish to express my gratitude to Professor Grigorian A. of the Moscow Academy of Science for his assistance in obtaining this microfilm.

This conclusion has been confirmed by the expert opinions of d'Alverny Marie-Thérèse Dr in Paris and Professor Dr Bernhard Bischoff in Munich, for whose personal communications I am deeply grateful.

Here one must remember that the Theorica was not ascribed to John of Seville until the fifteenth century, and that one should “not put too much faith in attributions of texts to John of Seville by copyists of the fifteenth century or by their modern cataloguers”, to quote Thorndike L. , “John of Seville”, Speculum, xxxiv (1959), 20–38.