Alfonso XI of Castile
A medieval king who unified a fractured Castile, crushed a Moorish invasion at Río Salado, and ruled with an iron fist to restore royal authority.
1311–1350 (age 39)·King of Castile, León and Galicia from 1312 to 1350·Birthday: August 13
Biography
Alfonso XI inherited the throne of Castile and León as an infant, plunging the kingdom into a turbulent period of rival regencies and noble power grabs. Coming of age, he seized control with a determination that earned him the epithet 'the Avenger.' His reign was defined by a dual focus: consolidating royal power against the overmighty nobility and pursuing the centuries-long Reconquista against the Muslim kingdoms in southern Iberia. His greatest military triumph came in 1340 at the Battle of Río Salado, where a combined Castilian-Portuguese force, aided by Aragonese and European crusaders, decisively defeated the Marinid sultanate of Morocco and its Granadan allies, effectively ending major African interventions in the peninsula. A shrewd and often ruthless administrator, he strengthened central institutions and legal codes, leaving a more stable and powerful kingdom, though his death from the Black Death during the siege of Gibraltar cut short his ambitious campaigns.
#1 When Alfonso Was Born
The biggest hits of 1311
Alfonso's Life & Times
The world at every milestone
1311Born
1316Started school
1324Became a teenager
1327Could drive
1329Could vote
1332Turned 21
1341Turned 30
1350Died at 39
Key Achievements
- Secured a decisive victory at the Battle of Río Salado in 1340, a critical turning point in the Iberian Reconquista.
- Implemented the Ordenamiento de Alcalá in 1348, a major legal code that strengthened royal law over local fueros (charters).
- Successfully ended the period of noble regencies and reasserted direct monarchical control over Castile.
- Led the prolonged Siege of Algeciras (1342-1344), one of the first European conflicts to see significant use of gunpowder artillery.
- Fostered a cultural flourishing in his court, patronizing the composition of the influential 'Libro de la Montería' on hunting.
Did You Know?
He was the only European monarch to die of the Black Death while actively leading a military campaign.
His long-term mistress, Eleanor de Guzmán, wielded significant influence and her sons founded the powerful Trastámara dynasty.
He was a contemporary and rival of the Moroccan sultan Abu al-Hasan Ali, whom he defeated at Río Salado.
The chronicle of his reign, the 'Crónica de Alfonso XI,' is a key primary source for 14th-century Castile.
He founded the Royal Chapel of the Cathedral of Córdoba as a burial site for himself and his father, though he was not interred there.
“Granada will be Christian again, or I will not be king.”
