The codex a.X.2.14=Lat. 209 - famous as De Sphaera and one of the most important at the Biblioteca Estense Universitaria (Estense Library) in Modena, Italy - is unanimously regarded as the most beautiful astrological book of the Italian Renaissance. It was illuminated by a refined artist of the Lombard school (thought to be Cristoforo de Predis) for the Milan court and reached the Estense in Ferrara via the frequent artistic and cultural exchanges between them and the Sforza. The codex sums up, with an unparalleled elegance, the astrological knowledge of its time and testifies the renewed authority, the reputation enjoyed by faith in the stars – a fashion and a culture at the same time – in the most powerful and refined courts. The De Sphaera adds its personal, superlative touch – with the splendour of its illuminated pages and the rhyming verses of its horoscopes – to a field, that of planet and zodiac iconography, which was already successful.
From folio 4v to folio 12r, the codex displays 15 fully illuminated pages of great richness. The illuminations, aesthetic and thematic climax of this work of art, show on each bifolio the effects that the astrological signs and the planets have on human behaviours.
The facsimile edition of the codex is printed on paper imitating the original parchment; a gold embossed decoration is heat impressed. The kidskin binding is stamped with the Visconti-Sforza coat-of-arms. The 120 page commentary contains a richly illustrated study by Gianni Venturi (Literature lecturer at the Florence University and director of the Istitute for Studies of the Renaissance in Ferrara), Giovanna Lazzi (art historian and director at the Riccardiana Library in Florence), Annalisa Battini (Librarian at the Biblioteca Estense Universitaria - Estense Library - in Modena) and Marco Bertozzi (lecturer at the University of Florence).