Witelo, the thirteenth-century author of an extensive treatise on optics entitled Perspectiva, was thoroughly acquainted with most of the optical works available in the Latin West at that time. Among the works he studied was Euclid's Optica (in a Latin translation under the title De visu). It is the purpose of this paper to demonstrate that in fact Witelo had produced an earlier recension of Euclid's treatise, a work not generally attributed to him. Although this earlier investigation into optics is also entitled Perspectiva, to avoid confusion it will be referred to here as the Recension. This Recension is found in the following manuscripts:
Florence, Bibl. Riccardiana, MS 885 (s. xiv) fols. 132r–143v (Props. 1–15, 18, 17–23, 26–28, 16).
Milan, Bibl. Ambrosiana, MS R. 47 sup. (s. xiii) fols. 133r–148r (Props. 1–23, 26–61).
Paris, Bibl. Nat., MS lat. 7366 (s. xiv) fols. 90v–97v (Props. 1–23, 26–34).
Paris, Bibl. Nat., MS lat. 10252 (a.d. 1476) fols. 159 (154)v–172 (167)r (Props. 1–23, 26–30).
Toruń, Ksiąžnica, Miejska im. Kopernika, MS Gymnasialbibl. R.4°.2 (s. xiv) pp. 3–30 (Props. 1–23, 26–61).
Vatican, Bibl. Apost. Vaticana, MS Vat. lat. 3102 (s. xiv) fols. 37v–50r (Props. 1–23, 26–61).
Vienna, Österr. Nat. Bibl. MS 5303 (s. xv–xvi) fols. 32r–41v (Props. 1–23, 26–30).