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Alfomso El Sabio

Alfomso El Sabio

(b. Toledo, Spain, 23 November 1221; d. Seville, Spain, 24 April 1284)

astronomy, dissemination of science and learning.

Alfonso el Sabio, “the learned,” was the son of Ferdinand III of Castile and León, and Beatrice of Swabia, granddaughter of Frederick Barbarossa. Upon the death of his father in 1252, he became Alfonso X. Descended from the Hohenstaufens through his mother, he sought between 1256 and 1272 to become Holy Roman Emperor by pressing the Swabian claims to that position. This continued preoccupation alienated the Castilian nobility and depleted his treasury. Upon the death of his eldest son, Ferdinand, in 1275, his second son, Sancho, sought to dethrone him and gain power. Seville remained loyal to Alfonso, but the majority of his subjects opposed him and the Cortes declared him deposed in 1282.

Although Alfonso’s domestic policies threatened the stability of the state, his patronage of science and learning sowed the seeds of later Castilian greatness. In the tradition of his predecessors, he supported the translation of Arabic works into Latin and Castilian. Alfonso gave Spain a great legal code, Las siete partidas, a compilation of the legal knowledge of his time. and sponsored important scientific translations. These translations of Arabic astronomical, astrological, and magical treatises reveal Alfonso’s active interest in science. He gained his most lasting scientific fame by supporting a new edition of the Toledan Tables of the Cordoban astronomer al–Zargālī (Arzachel, ca. 1029–ca. 1087). This new edition, the Tablas alfonsinas, was not an original work. Although new observations were made from 1262 to 1272, it still followed the general format of al–Zarqālī’s earlier compilation and, with only minor qualifications, retained the Ptolemaic system for explaining celestial motion. It utilized mean solar, lunar, and planetary orbits and equations; declination of stars; ascension, opposition, and conjunction of the sun and moon; visibility of the moon and of eclipses; and a trigonometrical theory of sines and chords to predict the motion of celestial bodies. The original Spanish edition of the Tablas has been lost. Its popularity in the medieval period was based on the Latin versions.

Alfonso also supported the translation of a series of Arabic astronomical studies known collectively as the Libros del saber de astronomia. The fifteen treatises in this collection are either based on or translated from Arabic astronomical works written in the ninth through the twelfth centuries. The collection, which includes a catalog of stars and a study of the celestial globe, spherical astrolabe, quadrants, clocks, and other assorted astronomical instruments, was prepared while observations were being made for the Alfonsine Tables. Never as popular as the latter, it was not published until 1863–1867. Alfonso may have also encouraged Rabi Zag of Toledo to prepare a treatise on the quadrant. Entitled Tratado del cuadrante “sennero,” it exists today in an incomplete manuscript; only eight of its thirteen chapters are extant, Alfonso is said also to have sponsored a vernacular translation of an Arabic work on magic, the Latin Liber picatrix. His reputation is based not on his occult endeavors but on the royal patronage he gave so willingly to astronomy.


The Alfonsine Tables may be found in numerous Latin editions, none of which is, in any sense, a critical edition. The 1st ed. of the Latin version is Alfonti … celestium motuum tabule: nec non stellarum fixarum longitudines ac latitudines Alfontii tempore ad moms veritatem mira diligentia reducte(Venice, 1483; 2nd ed., with canones of Joannes Lucilius Santritter, 1492). The Libros del saber de astronomia was ed. by Manuel Rico y Sinobas, 5 vols. (Madrid, 1863–1867). A beautiful color facsimile of Alfonso’s famous study on lapidaries has been reproduced by José Fernandez Montaña in Lapidario, reproducción fotolitográfica(Madrid, 1881). The fragmented Tratado del cuadrante “sennero” was ed. by Josè M.a Millas Vallicrosa in his Nuevos estudios sobre historia de la ciencia española (Barcelona, 1960). The work on magic was trans. by H. Ritter and H. Plessner in their Picatrix: Das Ziel des Weisen (London, 1962).

The definitive portrait of Alfonso’s political activities is Antonio Ballesterosy Baretta. Alfonso el Sabio (barcelona, 1963). Excellent brief biographies are John Esten Keller, Alfonso X, El Sabio (New York, 1967), and Evelyn S. Proctor, Alfonso X of Castile, Patron of Literature and Learning (Oxford, 1951). For his scientific works and translations see Evelyn S. Proctor, “The Scientific Works of the Court of Alfonso X of Castile,” in Modern Language Review, 40 (1945), 12–29; and Moritz Steinschneider, “Die europäischen Uebersetzungen aus dem Arabischen,” in Sitzungsberichte der Akademie der Wissenschaften in Wien. 4, 9, 40, 55, 60, 61, 69, 87, 93, 97, and 108 (1904–1905). For his astronomy and its influence see J. L. E. Dreyer. “The Original Form of the Alfonsine Tables,” in Monthly Notices of the Royal Astronomical Society, 80 (1920), 243–267; Jose Soriano Viguera, La astronomia de Alfonso X (Madrid, 1926); Pierre Duhem, Le système du monde, II, (Paris, 1914), 259–266; and Alfred Wegener, Die Alfonsinischen Tafeln für den Gebrauch eines modernen Rechners (Berlin, 1905), and “Die astronomischen Werke Alfons X,” in Bibliotheca mathematica, 6 (1905), 129–185.

Phillip Drennon Thomas

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