Alfonso X

Lore & Background

Alfonso's scientific interests—he is sometimes nicknamed the Astrologer (el Astrólogo)—led him to sponsor the creation of the Alfonsine tables, and the Alphonsus crater on the Moon is named after him. He also sponsored the work of historians who, for the first time since Isidore of Seville in c. 600, placed Spain in the context of world history. As a lawmaker he introduced the first vernacular law code in Castile, the Siete Partidas. He created the Mesta, an association of sheep farmers in the central plain, but debased the coinage to finance his claim to the German crown. He fought a successful war with Portugal, but a less successful one with Granada. The end of his reign was marred by a civil war with his eldest surviving son, the future Sancho IV, which continued after his death.

Reader's Guide

Alfonso X succeeded his father as King of Castile and León in 1252. The following year he invaded Portugal, capturing the Algarve. King Afonso III of Portugal surrendered, but later reached an agreement to marry Alfonso's daughter Beatrice, returning the captured land to their heirs. In 1261 Alfonso captured Jerez, and in 1263 he returned Algarve to Portugal, signing the Treaty of Badajoz (1267).

In 1254 he signed a treaty of alliance with Henry III of England, and his half-sister Eleanor married Henry's son Edward; with this act Alfonso renounced forever all claim to the Duchy of Gascony. In 1256, on the death of William II of Holland, Alfonso's descent from the Hohenstaufen gave him a claim to the German crown. His election as German king by prince-electors encouraged expensive schemes that never succeeded. He never traveled to Germany, and his alliance with Ezzelino IV da Romano deprived him of papal support.

To obtain money, he debased the coinage and tried to prevent a rise in prices by an arbitrary tariff. His nobles rebelled in 1272, but reconciliation was brought about by his son Ferdinand in 1273. After Richard of Cornwall's death, the German princes elected Rudolph of Habsburg (1273), and Alfonso was declared deposed by Pope Gregory X. In 1275 Alfonso tried to meet his imperial vicar in Italy but was halted by the Pope, who obtained Alfonso's oral renunciation of claims to the Holy Roman Empire.

Throughout his reign, Alfonso contended with nobles. His eldest son Ferdinand died in 1275, and his second son Sancho claimed the throne, leading to a civil war. Alfonso was forced in 1282 to accept Sancho as his heir. He died at Seville in 1284, leaving a will that tried to exclude Sancho.

Did You Know?

• Alfonso X was born on 23 November 1221 in Toledo, Kingdom of Castile.
• He married Violante, daughter of King James I of Aragon, in 1249.
• He created the Mesta in 1273, an association of sheep holders.
• He is one of 23 lawmakers depicted in the U.S. House of Representatives chamber.