It was founded in 910 when the Christian princes of Asturias along the northern coast of the peninsula shifted their capital from Oviedo to the city of León.

In 1008, Norman Vikings attacked Galicia, destroying Santiago de Compostela and seventeen other towns, while Olaf Haraldsson of Norway raided Spain's Atlantic coast.

The Kingdom of León expanded south beyond the Douro, and then beyond the Sistema Central in the 10th, 11th and 12th centuries into the so-called Extremadura Leonesa, whose southern frontier was primarily settled by military orders.

Ordoño II was also a military leader who brought expeditions from León south to Seville, Córdoba, and Guadalajara, in the heart of the Muslim territory.

As the Leonese troops advanced they were followed by a process of repoblación, which consisted of repopulating the Meseta high plains, with people coming from Galicia and especially from Asturias and León.

[11] The defeat in the Battle of Fornelos left Galicia without an authority capable of facing the Vikings, who for three years camped comfortably, looting different Galician regions.

In 971, Gunrod and his Vikings were surprised and defeated by Count Gonzalo Sánchez upon return towards Ría de Ferrol (where they had their stranded ships).

It was led by Ulv Galiciefarer, who tried to go to the Riá de Arousa area and then became a mercenary for Rodrigo Romániz, but was defeated by the bishop of Compostela.

However, Sancho III of Navarre (1004–1035) took over Castile in the 1020s, and managed León in the last year of his life, leaving Galicia to temporary independence.

Thus, though scarcely influenced by the culture of the successor territories of the former Caliphate, Ferdinand I followed the example of the counts of Barcelona and the kings of Aragon and became hugely wealthy from the parias of the Taifas.

When he died in 1065, his territories and the parias were split among his three sons, of whom Alfonso emerged the victor in the classic fratricidal strife common to feudal successions.

Modern historians see the fall of Toledo as marking a basic change in relations with the Moorish south, turning from the simple extortion of annual tribute to outright territorial expansion.

Alfonso VI thus found his role as a Catholic king redefined as he governed large cities with sophisticated urban, Muslim subjects and growing Christian populations.

Alfonso IX, besides conquering the whole of Extremadura (including the cities of Cáceres and Badajoz), was the most modern king of his time, founding the University of Salamanca in 1212 and summoning in 1188 the first parliament with representation of the citizenry ever seen in Europe,[15] the Cortes of León.

[citation needed] Alfonso IX did not want his kingdom to disappear upon his death and designated his heirs as Sancha and Dulce, the daughters of his first wife.

This artistic expression, rooted in Visigothic and Andalusian traditions, produced structures ranging from modest single-nave churches to elaborate monastic complexes.

[17] Key figures, including monarchs and ecclesiastical leaders, played a pivotal role in shaping this art, with a notable infusion of Andalusian tastes.

[19] In the realm of painting, illuminated manuscripts like the "beatos" exemplify the vibrancy and evolution of Leonese art, incorporating elements from Byzantine-Merovingian influences to an Islamic-Carolingian character.

The culture of the Kingdom of León was notable for its richness and diversity, reflecting its position as a political and religious center of Christianity in the Iberian Peninsula.

Key Latin literary works such as the Codex Vigilanus and the Historia Legionense documented the kingdom’s history and helped consolidate its legacy.

The Fueros de León (1017), promulgated by Alfonso V, established a legal framework that was advanced for its time, while texts like the Glosas Emilianenses marked a significant step in the transition from Latin to Romance languages.

Another notable work of this period is the Codex Calixtinus, a manuscript linked to the Camino de Santiago, which served as a guide for pilgrims and underscored the cultural and spiritual importance of the pilgrimage, reinforcing León’s connection to European Christianity.

Monasteries and churches such as San Isidoro de León, Tábara, Samos, and Sahagún became key centers for intellectual and artistic production.

Pilgrims traveling through León brought with them new ideas, artistic styles, and liturgical practices, strengthening the kingdom’s ties with the rest of Europe.

They also promoted the construction of hospitals, churches, and hostels, facilitating the organization of reconquered territories and integrating cultural and economic networks within the kingdom.