JOHANNES DE SACRO BOSCO (d.1256 [1244?]). Sphaera mundi. - GERARDUS CREMONENSIS (c. 1114-1187). Theorica planetarum. Venice: Franciscus Renner, de Heilbronn, 1478.

First illustrated edition of these important works of medieval astronomy; third appearance of both texts. Where the earlier editions had left blank spaces for the scientific diagrams, Renner made a printing innovation by using a set of woodcuts. The Sacrobosco and Gerardus texts, which explain the theoretical workings of the universe, were of like brevity and remained standard university texts through the middle ages and to almost the end of the Renaissance. The former was required reading for the A.B. degree at Oxford in 1409, and though Barocius in 1570 pointed out some eighty-four errors, it continued to be read for a further eighty years. Essling 257; HC *14108; Klebs 874.6; Sander 6659; Goff J-402; ISTC ij00402000.

Chancery quarto (200 x 147mm). 48 leaves. Incipits to each work printed in red. 11 diagrams, woodcut white-on-black floreated initials. (Single marginal wormhole, small marginal tear and some soiling to first leaf, occasional faint spotting.) 18th-century paper boards (slightly stained, spine chipped); chemise and slipcase. Provenance: faded inscription on a1 – Anselmus Doll. (18th-century inscription to flyleaf) – [Boston University Libraries (bookplate removed; deaccessed)] – Christie's, 6 June 2007, lot 127.