The Books of the Wisdom of Astronomy by Alfonso X, the Learned

This work contains Arabic and Jewish scientific texts translated into Latin, and from the Latin into Castilian. The Books draw primarily from texts dating from 1254 to 1259. These sources were later compiled in the decade 1270 to form the present work which is divided into sixteen sections. Two hundred and one folios, written by a single hand in Gothic script, have been recovered to this day. Only a few pages are missing; its condition is fair as the illuminated parchment was restored in 1977.

This is one of the major scientific works directed by Alfonso X, the Learned. In addition to the translators from the Toledo School, a great number of copyists and miniaturists participated in its elaboration.

Astrology and astronomy, the book’s principal themes, were the king’s primary interests—he wrote a prologue for each one of the books. The work incorporates three types of studies: those that treat the movement of the stars, those about constructing astronomical and astrological instruments and, finally, those concerning the measurement of time. The king essentially wanted there to be a treaty for each instrument, a treaty explaining its construction and another for its use. Books that already existed on these themes were translated into Castilian and integrated into the project. For each subject that had not been treated, he had a treaty drawn up. While The Book’s aim was to summarize Arabic and Jewish Medieval science, a number of new writings were thus added, giving this work its specificity.

The manuscript is illuminated: we will notice, for instance, the careful working of the capital letters for each word of each section, the work in the margins, the small illustrations and the one hundred and sixty-two grand miniatures. Instruments used to measure time, the subjects of astronomy and astrology, such as the astrolabe that was so characteristic of the period, are studied in great detail. Here we have a thorough exploration of how the stars and planets were studied in the Middle Ages. The figurative representations illustrating the heavenly bodies make of The Books of the Wisdom of Astronomy and the other works directed by Alfonso X, the Learned didactic works.

In terms of the Arabic and Jewish sources used for this project, the major sources were the writings of Azarquiel and ‘Abd al-Rahmân al-Sûfî, a Persian astronomer from the 10th century who contributed to the translation and diffusion of the Greek astronomers (in particular Ptolemy), who were known in the West thanks to the translations and corrections carried out by Islamic scholars. Thanks to The Books, a large part of Medieval Arabic and Jewish scientific learning could be transmitted to the rest of Europe by the intermediary of al-Andalus. This work can thus be considered a synthesis of the current knowledge of three cultures. Five Jews, four Spanish Christians, four Italians and one converted Muslim closely participated in its elaboration.

The Books have furthermore served as the groundwork for the ‘Tables of Alfonso’ (Tablas Alfonsíes), a masterwork of the literature realized under the direction of Alfonso, the Learned. The literary production carried out by Alfonso X forms a homogeneous ensemble. In addition to The Books, the major works he sponsored are the following[1]:

- the ‘Songs’ (Cantigas)

- the ‘Lapidary’ (Lapidario)

- the ‘Book of Board Games’ (Libro de los Juegos)

- the ‘General history’ (General e Grande Estoria)

- the ‘Toledo Tables’ (Tablas Toledanas) which includes the former.