Book of the Eighth Sphere Facsimile Edition

The Book of the Eighth Sphere is an illuminated manuscript, made between 1542 and 1562, of a treatise on the constellations attributed to Alfonso X, "the wise," King of Castile and Leon. It comprises forty-six full-page round diagrams, each centered on a constellation (or two constellations) of the fixed stars. An explanation, with citations of ancient sources, is included for each diagram. The handsome codex was made for a member of the powerful Álvarez de Toledo family.

The Castillian text is a translation, adaptation, and amplification of the Arabic-language Book of the Constellations by the tenth-century Persian astronomer al-Sūfī, followed by a summary that relies on the ancient Greek astronomer Ptolemy's Almagest (as transmitted in Arabic and Latin).

Pleasing and Orderly Presentation

The manuscript's visual interest lies in its circular diagrams, of which there are forty-six, rather than the expected forty-eight constellations described by Ptolemy and al-Sūfī because two pairs of constellations are combined in this treatment, Serpens with Ophiuchus (the serpent with the serpent-bearer) and Lupus with Centaurus (the wolf with the centaur).

At the center of each diagram is a naturalistic representation of the constellation(s), with the stars indicated by gold dots. Argo Navis ("the ship Argo") is shown as a grand contemporary galleon with three masts. In the spandrels are amusing cranes, one in each corner lifting a stone with one of its legs, a symbol of vigilance (fol. 11r).

Copied from an Alfonsine Original

The manuscript is a copy of the opening chapter of a much-damaged manuscript of the Book of the Wisdom of Astrology (or Books of the Wisdom of Astronomy) dating from the time of the text's compilation in the thirteenth century: Madrid, Biblioteca Histórica Marqués de Valdecilla de la Universidad Complutense, MS 156. The sixteenth-century copy is thus an essential witness to the Alfonsine text.

The Northern and Southern Skies

The leaves of the manuscript are now out of order. Originally, the constellations were presented in three sections devoted to the northern sky (21 constellations in 20 diagrams), the zodiac (12 diagrams), and the southern sky (15 constellations in 14 diagrams).

Coats of Arms among the Stars

The manuscript was made for a member of the Álvarez de Toledo family, the then-reigning dukes of Alba. The Álvarez de Toledo coat of arms repeatedly appears in the manuscript, for example, in the spandrels of the circular diagram devoted to Ursa Minor, originally the manuscript's opening diagram (fol. 36v).

Now Coupled with an Alfonsine Lapidary

The Book of the Eighth Sphere must have entered the royal library in or before 1684. At that time, an inscription appraising its value was added (fol. 1r). In the eighteenth century, it was bound together with a sixteenth-century copy of Alfonso's lapidary, which had been acquired by the royal library more recently. The resulting codex constitutes today's MS 1197, the astronomical text on parchment (fols. 1-49) and the lapidary on paper (fols. 50-163).