The Medieval Kingdoms of the Iberian Peninsula: Castile, Aragón, and Al-Andalus

Posted on Oct 17, 2025 in Geography

The Christian Kingdoms of the North

The Kingdom of Asturias and León

The Kingdom of Asturias began when Pelayo defeated the Muslims in the Battle of Covadonga in 722. This event was later considered the start of the Christian Reconquest of Al-Andalus. Under Pelayo’s successors, Oviedo became the capital. Alfonso III (866–910) advanced the territory significantly due to conflicts within the Emirate of Córdoba. In the 10th century, the capital moved to León, establishing the Kingdom of León.

The Crown of Castile (1035–1492)

Fernán González (930–970) established his authority over all Castile, though he remained a vassal of the King of León. Fernando I became King of Castile in 1035, and in 1037, he also became King of León. The union split again in 1157 between Fernando II (León) and Alfonso VIII (Castile). The definitive union occurred when Fernando III inherited Castile in 1217 and León in 1230, forming the Crown of Castile.

Castilian Institutions and Governance

The Crown of Castile maintained unified institutions and laws, centered around the monarch. Key governing bodies included:

  • Parliament (Cortes): Composed of noblemen, clergy, and representatives of cities.
  • Royal Council: Advised the King.
  • High Court (Audiencia): Held judicial authority.
  • Council (Consejo): The main governing body.
  • Chief Magistrate (Corregidor): Represented the King in cities, performing judicial and military functions.

The Mesta and the Wool Trade

After Castile conquered Extremadura and Andalusia, transhumance (seasonal movement of livestock) developed on a very large scale. Sheep traveled along routes called cañadas, moving to northern Castile in the summer and to the south in the winter. In 1273, sheep owners united in an association called the Mesta. The wool of the Merino sheep led to a boom in trade fairs, fostering significant trade and artisan activity.

Internal Conflicts and the Trastámara Dynasty

The late medieval period was marked by severe problems:

  • Economic Crisis: Population fell, and agricultural land was abandoned.
  • Peasant Revolts: Nobles, receiving less income, raised taxes, leading to widespread peasant uprisings.
  • Noble Rebellions: Nobles frequently fought to seize each other’s lands.

The most important conflict was the civil war of Enrique of Trastámara against King Pedro I. The King was killed, and Enrique II became monarch in 1369, marking the beginning of the Trastámara dynasty. In the 15th century, Castile took possession of the Canary Islands.

The Kingdoms of the Pyrenees

Following the collapse of the Carolingian Empire, Charlemagne established the Hispanic March (a defensive frontier). By the 9th century, this area broke apart, leading to the formation of independent entities:

  • Aragón: Aragón, Sobrarbe, and Ribagorza broke free from Carolingian control. Aznar Galíndez rose to power in Aragón around 820.
  • Catalan Counties: Also developed independently.

Navarre and the Jimena Dynasty

Íñigo Arista declared himself King of Pamplona, which expanded and later became the Kingdom of Navarre, ruled by the Jimena dynasty. Sancho III expanded the kingdom to include Aragón, Castile, and part of León. After Sancho’s death in 1035, the kingdom was divided among his sons:

  • García Sánchez (1035–1054): Navarre
  • Fernando I (1035–1065): Castile
  • Ramiro I (1035–1063): Aragón
  • Gonzalo (1035–1045): Sobrarbe and Ribagorza

The last king of Navarre was Sancho VII the Strong (d. 1234). Navarre was finally conquered by Fernando the Catholic in 1512.

The Crown of Aragón

Formation and Institutions

The Kingdom of Aragón was initially united with Navarre until 1134. It increased its territory, and in 1137, Ramón Berenguer IV married Petronilla of Aragón. This union led to the creation of the Crown of Aragón, a federation of states comprising the Catalan Counties, the Kingdom of Aragón, Valencia, and Mallorca.

The King headed all institutions, but each territory maintained its own parliament (Cortes). Key regional institutions included:

  • Generalitat: Held an administrative role in Catalonia and Valencia.
  • Justicia: In Aragón, this office defended the people’s rights and privileges against the King.

Expansion and Economy

The Crown of Aragón expanded significantly:

  • 12th Century: Alfonso I the Battler conquered the Ebro valley.
  • 13th Century (Jaime I the Conqueror): Took Valencia, Alicante, Murcia, and the Balearic Islands.
  • 13th Century (Pedro III the Great): Expanded into the Mediterranean, conquering Sicily, Sardinia, and Naples.

The economy varied greatly across the Crown:

  • Aragón: Primarily rural, focused on agriculture and livestock farming.
  • Catalonia: Developed a strong manufacturing industry, specializing in textiles, ironwork, and naval construction.
  • Valencia: An important trading center, utilizing Consulates of the Sea—offices that settled disputes between merchants.

Challenges in the Crown of Aragón

The 14th and 15th centuries brought severe crises:

  • Black Death: The plague killed a large portion of the population, particularly in Catalonia (1348).
  • Succession Crisis: The Trastámara dynasty took power in 1412 when Martín I died without heirs, and Fernando of Antequera became King.
  • Peasant Revolts: Demographic decline led nobility to impose extra taxes and obligations. Remensa peasants rebelled against the nobility.
  • Urban Conflicts: Civil war (1462–1472) erupted between nobles and rich merchants (defending traditional privileges) and smaller merchants, artisans, and the poor.

Al-Andalus: Muslim Rule in the Iberian Peninsula

In 711, the Muslim ruler Musa defeated Roderic in the Battle of Guadalete, conquering most of the Iberian Peninsula within a few years. They named the territory Al-Andalus, with its capital established at Córdoba.

The Emirate and the Caliphate of Córdoba

Initially, Al-Andalus was dependent on the Umayyad Caliphate in Damascus. When the Abbasid dynasty took power in the 8th century, members of the ruling Umayyad family were killed. Abd al-Rahman escaped to the Iberian Peninsula and founded the independent Emirate of Córdoba (756–929).

Abd al-Rahman III later founded the Caliphate of Córdoba (929–1031), strengthening his authority. Córdoba became a major marketplace and cultural center. Although Hisham II became Caliph in 976, the general Almanzor became the real ruler. After Almanzor died in 1002, the Caliphate collapsed in 1031.

Fragmentation and the Nasrid Kingdom of Granada

The collapse of the Caliphate led to the division of Al-Andalus into small, poorly organized states known as Taifas. Christian kingdoms attacked these states, forcing their rulers to pay protection money (parias). The Christians captured Toledo in 1085.

The Taifas sought help from North Africa, leading to two successive waves of imperial rule:

  1. Almoravids (1086): Initially strong, their power waned, leading to a second Taifa period in the 1140s.
  2. Almohads (1147): Also initially strong, their power was broken by the Christian kingdoms in the decisive Battle of Las Navas de Tolosa in 1212.

Following the Almohad collapse, the Christians conquered almost the entire peninsula, leaving only Granada. The Nasrid Kingdom of Granada survived because it paid tribute to Castile. It was finally conquered by the Catholic Monarchs in 1492.