King of Castile and León who commissioned the Siete Partidas, the Alfonsine Tables and the Cantigas de Santa Maria, and whose pursuit of the imperial crown ended in rebellion and deposition.
Alfonso X ruled Castile and León from 1252 to 1284 and used the crown as an instrument of learning: a law code meant to govern every relationship in the kingdom, astronomical tables computed at Toledo, a history of Spain and a history of the world written in Castilian prose, and more than four hundred songs to the Virgin set to music. Almost none of it took effect on his own terms — the law code that carries his name became binding only in 1348, sixty-four years after his death.
The same reign spent two decades and a great deal of Castilian silver on the fecho del Imperio, his campaign to be crowned Holy Roman Emperor as a grandson of Philip of Swabia. He gave the claim up before Pope Gregory X at Beaucaire in 1275, the year his heir Fernando de la Cerda died and a Marinid army crossed from Morocco. Seven years later an assembly at Valladolid transferred the exercise of royal power to his second son Sancho, and Alfonso died at Seville in 1284 holding little more than that city, Murcia and Badajoz.
Alfonso was born at Toledo on 23 November 1221, the eldest son of Ferdinand III of Castile and Beatrice of Swabia. His mother was a daughter of Philip of Swabia and a granddaughter of Frederick Barbarossa, and that descent supplied the claim he would chase for twenty years. His father supplied the opposite kind of inheritance: a kingdom in the middle of the fastest advance the Reconquista ever made.
He was raised in Galicia and León in the household of García Fernández de Villamayor and came of age on campaign. As heir he negotiated the submission of Murcia in 1243, where the Treaty of Alcaraz turned the taifa into a Castilian protectorate that kept its own Muslim ruler, and he served in the Andalusian war that ended with his father taking Seville in 1248. In January 1249 he married Violant, daughter of James I of Aragon, and when Ferdinand died on 30 May 1252 Alfonso was king within two days.
Alfonso is unusual among medieval kings in that a great deal of his own voice survives, because he wrote himself into his books. The prologues speak in the first person of a king who commissions, corrects and orders the work of others, and who thinks the ordering is itself royal labour. The Cantigas de Santa Maria go further and cast him as the Virgin’s own troubadour, showing him kneeling, ill, and rescued by her; the satirical cantigas de escarnio attributed to him show a much sharper register, mocking and obscene by turns, with a taste for a well-aimed joke at a nobleman’s expense.
Hostile memory arrived quickly. The Crónica de Alfonso X, compiled under the descendants of the son who deposed him, presents a king whose taxes, debased coinage and imperial spending wore the kingdom out, and whose stubbornness turned a manageable succession dispute into a war. The Castigos written in Sancho IV’s name are a son’s implicit case against a father. Against that, later Castilian tradition made him the Rey Sabio, the king of the books, and lent him stories he never generated: the best known — that he said he would have advised the Creator on a simpler arrangement of the heavens — is not contemporary and appears only centuries after his death.
Modern historians, Joseph O’Callaghan and H. Salvador Martínez among them, have tried to hold the two portraits together. They credit a genuinely curious and methodical patron, generous to Jewish, Muslim and Christian scholars alike and serious about making Castilian carry learning; they also find a ruler who would not let go of a lost cause, who alienated the nobility with fiscal experiments, and who handled his own sons badly. What is hardest to dispute is the persistence: he kept the imperial claim alive for eighteen years after the German princes had moved on, and kept the scriptorium working while his kingdom broke apart around him.
Alfonso legislated from the beginning of the reign. The Espéculo of about 1255 and the Fuero Real, granted to town after town in the same years, were attempts to put royal law where municipal custom had stood alone. The great work, compiled between 1256 and 1265 and known from the fourteenth century by the number of its parts, was the Siete Partidas: seven books running from the church and the articles of faith through kingship, justice and procedure, property, marriage and inheritance, wills, and crime and punishment.
What made it radical was its sources and its language. The Partidas are built on the Roman law revived at Bologna and on the canon law of the Decretals — the learned ius commune of the thirteenth century — and they are written in Castilian, for a kingdom whose towns had governed themselves by local fueros granted one by one. The code therefore claimed for the king a jurisdiction that the towns and the nobility had no intention of conceding, and the rebellion of 1272 turned in part on exactly that grievance.
It did not take effect in his lifetime. Only in 1348 did his great-grandson Alfonso XI of Castile, in the Ordenamiento de Alcalá, give the Partidas the force of law as a subsidiary code, ranking behind royal ordinances and the municipal fueros but supplying everything they left unsaid. In that role it became the reference law of Castile for centuries and travelled with Castilian rule to the Americas.
Toledo had been translating Arabic science into Latin for a century before Alfonso, and his workshop changed the destination language. Jewish scholars such as Yehuda ben Moshe ha-Cohen and Isaac ibn Sid, working with Christian clerics and with converts from Islam, rendered Arabic astronomy, astrology and magic into Castilian: the Libro del saber de astrología, the Lapidario on the powers of stones, the Picatrix, and the Libro de los juegos of 1283 on chess, dice and tables.
The most consequential product was the set of astronomical tables that carries his name. Compiled at Toledo from the 1260s onward, they corrected and replaced the Toledan Tables of al-Zarqālī for a new meridian and a new epoch dated to Alfonso’s accession in 1252. Recast at Paris in the 1320s, the Alfonsine Tables became the standard tool for computing planetary positions across Latin Europe and stayed in use for more than two centuries, which is why a crater on the Moon carries his name.
The same workshop produced the Estoria de España and the unfinished General Estoria, a history of Castile and a history of the world assembled from Latin, Arabic and Hebrew sources. Their importance is not only what they record but that they exist in Castilian prose at all: the reign fixed a written standard for the language and made it usable for law, history and science at once.
The Cantigas de Santa Maria are a collection of more than four hundred songs in Galician-Portuguese, the language of lyric poetry in thirteenth-century Iberia, written down with musical notation. Most narrate a miracle of the Virgin; every tenth song is a hymn of praise instead. They survive in four manuscripts, two of them at El Escorial, and the illuminated Códice Rico devotes a full page of panels to each song it covers.
The collection is the largest body of notated vernacular monophony to survive from the Middle Ages, which makes it a primary source for medieval music as well as for devotion. Its miniatures are just as valuable to historians for a different reason: they show instruments, clothing, ships, shops and sickrooms in colour, including Muslim and Jewish figures in a kingdom Alfonso ruled over all three communities. Several songs place the king himself in the story, cured or protected by the Virgin, so the collection doubles as a portrait of how he wished to be seen.