Work C.1.10

# Johannes de Wasia (?)

Commentum super Almagesti Ptholomei

This work, previously known as the ‘Erfurt Commentary’ (Zepeda), consists of a commentary on and a reworking of *Almagest* I.9-II.11 in Gerard of Cremona’s translation (A.1.2) arranged by propositions and proofs. Enunciations are close to those of the *Almagesti minor* (C.1.4), but the rest of the text differs. All four manuscripts date from the second half of the fourteenth century and the earliest of these seems to be MS Erfurt, UFB, Dep. Erf. CA 2º 375, copied by Johannes de Wasia (see C.1.9) probably in Paris in or after 1369. Zepeda (*The First Latin Treatise*, 91) suspects that the author ‘did not use the *Almagesti minor* itself, but a manuscript of the *Almagest* with some excerpts of it in the margins’. This matches exactly what we find in MS Erfurt, UFB, Dep. Erf. CA 2º 375, where the commentary is preceded (f. 85r-88r and 93r-112v) by a copy of *Almagest* I.9-II.12 with excerpts of the *Almagesti minor* added in the margins, all in Johannes de Wasia’s hand. This manuscript is therefore likely to be the original copy (or, at least, very close to the original copy), in which case Johannes de Wasia would be a plausible author for the commentary, something which also makes sense in view of the fact that Johannes de Wasia’s *Annotationes in Almagesti* (C.1.9) open with *Almagest* II.12. MS Dijon, BM, 441 (266) contains an expanded version of the commentary, including a preface (‘Quelibet circumferentia circuli secundum astrologos…’) and a continuation for *Almagest* II.12-13, which is perhaps the work of Jean Fusoris (*c.* 1365-1436). In MS Erfurt, UFB, Dep. Erf. CA 2º 375, the text is followed by a supercommentary (C.1.11) on f. 127r-129v.

**Text **‘(Erfurt, UFB, Dep. Erf. CA 2º 375) Commentum super Almagesti Ptholemei. Data circuli dyametro latera decagoni, penthagoni, hexagoni, tetragoni et trianguli omni ab eodem circulo circumscriptorum invenire… Pro probacione istius proposicionis supponitur quod linea divisa — erit angulus DEA notus orientalis super orizontem, quod est propositum.’

**Bibl. **R. Lorch, ‘Some Remarks on the *Almagestum parvum*’, in *Amphora. Festschrift für Hans Wussing zu seinem 65. Geburtstag*, eds S. S. Demidov, M. Folkerts *et al.*, Basel-Boston-Berlin, 1992, 407-438: 421-422 (reprinted in R. Lorch, *Arabic Mathematical Sciences. Instruments, Texts, Transmission*, Farnham-Burlington, 1995, V); H. Zepeda, *The Medieval Latin Transmission of the Menelaus Theorem*, PhD dissertation, University of Oklahoma at Norman, 2013, 184-221; H. Zepeda, *The First Latin Treatise on Ptolemy’s Astronomy: The Almagesti minor (c. 1200)*, Turnhout, 2018, 89-91.

**Modern ed. **Partial critical edition in Zepeda, *The Medieval Latin Transmission*, 493-572 (from all four manuscripts).

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