King Ferdinand I’s death led to the partition of his realms among his sons, setting up Alfonso VI’s initial rule in León (and subsequent struggles that shaped Castile-León’s leadership in the Reconquista).
After the death of his brother Sancho II, Alfonso VI recovered León and inherited Castile, reuniting the two crowns and consolidating a powerful base for expansion against the taifa kingdoms.
Alfonso VI proclaimed himself imperator totius Hispaniae (“emperor of all Spain”), signaling León-Castile’s claim to leadership among Iberian Christian polities during the Reconquista.
Alfonso VI occupied Toledo in May 1085, a major strategic and symbolic breakthrough that shifted the frontier southward and strengthened León-Castile’s position in central Iberia.
The Battle of Sagrajas (Zalaca) brought a major Almoravid-led coalition victory over Alfonso VI, marking the start of sustained North African intervention that slowed Christian advances.
At Uclés, Almoravid forces defeated León-Castile; Alfonso VI’s son and designated heir, Sancho Alfónsez, was killed, intensifying the succession crisis later inherited by Queen Urraca.
Queen Urraca ruled León and Castile from 1109 to 1126; her contested authority and civil strife shaped the political environment inherited by her son Alfonso VII.
Alfonso VI died in 1109 and was succeeded by his daughter Urraca, whose reign (amid conflict with Alfonso I of Aragon) affected León-Castile’s stability during continued Almoravid pressure.
Upon Urraca’s death, Alfonso VII became king of León and Castile (1126–1157), restoring stronger royal authority and reviving the imperial project in western Iberia.
Alfonso VII was crowned emperor in León in 1135, the ceremonial high point of the medieval Iberian “imperial” idea and an assertion of León-Castile’s primacy among Christian kingdoms.
A coalition led by Alfonso VII captured the major port of Almería in 1147, demonstrating León-Castile’s ability to project power with Mediterranean allies during the mid-12th-century Reconquista.
Alfonso VII died in 1157 and, following established practice, his realms were divided between his sons—Castile to Sancho III and León to Ferdinand II—ending the effective unity of León-Castile for a generation.
Castile and León concluded the Treaty of Sahagún, establishing peace between Sancho III of Castile and Ferdinand II of León—an important step in reducing Christian infighting that hindered Reconquista campaigns.
After Sancho III’s short reign, Alfonso VIII became king of Castile in 1158 while still a child, ushering in a turbulent minority that later gave way to an assertive Castilian leadership in the Reconquista.
In 1179, Alfonso VIII of Castile and Alfonso II of Aragon agreed on a future line of demarcation for conquest in al-Andalus, aiming to prevent disputes over territory as the Reconquista advanced.
The Almohads inflicted a major defeat on Alfonso VIII at Alarcos, checking Castilian expansion and setting the stage for renewed Christian coalition-building leading up to 1212.
Alfonso VIII led a multi-kingdom coalition to a decisive victory over the Almohads at Las Navas de Tolosa, widely regarded as a turning point that broke Almohad power in Iberia and accelerated later Castilian advances.
Alfonso VIII died in October 1214, ending a reign marked by early instability, the setback at Alarcos (1195), and the major victory at Las Navas de Tolosa (1212) that reshaped the Reconquista’s momentum.
Rise of Castile: Alfonso VI to Alfonso VIII (1065–1214)
