The eleventh-century taifas, weakened by their disunity, had fallen piecemeal to the Castilians, who had reason to anticipate the completion of the Reconquest.

When Toledo was lost in 1085, the alarmed amirs had appealed for aid to the Almoravids, a militant Berber party of strict Muslims, who in a few years had won control of the Maghreb (northwest Africa).

The Almoravids had incorporated all of Al Andalus, except Zaragoza, into their North African empire.

They had attempted to stimulate a religious revival based on their own evangelical brand of Islam.

In Spain, however, their movement had soon lost its missionary fervor.

The Almoravid state has fallen apart by the mid-twelfth century under pressure from another religious group, the Almohads, who extend their control from Morocco to Spain and make Seville their capital.

The Almohads share the crusading instincts of the Almoravids and pose an even greater military threat to the Christian states, but their expansion is stopped decisively in the epic battle of Las Navas de Tolosa (1212), a watershed in the history of the Reconquest.

Muslim strength ebbs hereafter.

Ferdinand III takes Seville in 1248, reducing Al Andalus to the emirate of Granada, which had bought its safety by betraying the Almohads' Spanish capital.

Granada remains a Muslim state, but as a dependency of Castile.

The Rise of Castile: From Frontier Buffer to Kingdom (10th–13th Century)

In the 10th century, the Kingdom of León establishes a series of strongholds along the upper Ebro River to serve as a buffer zone against Muslim incursions. This region, known as Castile ("land of castles"), is settled by border warriors and free peasants willing to defend it.

To encourage settlement and fortify the frontier, the kings of León grant fueros (special privileges and immunities) to the inhabitants, making Castile virtually autonomous. Over time, Castile develops into a distinct society, shaped by:

• A unique dialect and customs,
• A warrior culture, where all men are considered equals in battle, and
• A hereditary military caste, which is "democratized" by the frontier conditions—all warriors are equals, and all men are warriors.

The Emergence of the Kingdom of Castile

• In 981, Castile becomes an independent county under Count García Fernández.
• In 1004, it is elevated to a kingdom, marking its full emergence as a sovereign entity.

The Unification of Castile and León

Throughout the 11th and 12th centuries, Castile and León are periodically reunited through dynastic marriages but repeatedly divided among heirs, preventing lasting unity.

However, in 1230, King Ferdinand III of Castile (d. 1252) permanently unites the two kingdoms, forming a single political entity. This marks a turning point in the Reconquista, as the unified kingdom becomes the dominant Christian power in Iberia, paving the way for the eventual conquest of Muslim-held territories.

Diego de Acebo, bishop of Osma from 1201, had traveled to Denmark via southern France in 1203 or 1204, accompanied by his canon, Dominic de Guzmán, to secure a bride for crown prince Ferdinand, son of Alfonso VIII of Castile.

When they crossed the Pyrenees into southern France, Dominic and Diego had encountered the Cathars, a Christian religious sect with gnostic and dualistic beliefs, viewed by the Roman Catholic Church as heretical.

The Cathars ordain women as well as men; their clergy are celibate, vowed to poverty, and not subject to the pontiff's rule.

They made a second journey in 1204 or 1205 intending to bring the girl back with them, but found that she had meanwhile died.

They returned by way of Rome, where Diego had unsuccessfully petitioned Pope Innocent III to be entrusted with a mission to the northern pagans.

Instead, continuing their journey via Citeaux, Diego and Dominic have begun the work of conversion of the Cathars.

Folquet, as Bishop of Toulouse (now traditionally referred to by his proper name, Foulques, Fulk, or Folc, instead of the diminutive Folquet) takes a very active role in combatting heresy.

Throughout his episcopal career he will seek to create and encourage outlets for religious enthusiasms that are Catholic in an effort to woo believers away from preachers of heresy (primarily Cathar and Waldensian).

In 1206, he creates what will become the convent of Prouille to offer women a religious community that would rival (and, where necessary, replace) those of the Cathars.

Atlantic Southwest Europe (1216–1227 CE): Portuguese Administrative Reforms, Leonese-Castilian Diplomatic Realignments, and Navarrese Stability

Between 1216 and 1227 CE, Atlantic Southwest Europe—including Galicia, northern and central Portugal, Asturias, Cantabria, and northern Spain south of the Franco-Spanish border (43.05548° N, 1.22924° W)—underwent significant administrative centralization, diplomatic realignments, territorial consolidation, and cultural continuity. Portugal, under King Afonso II (1211–1223 CE) and subsequently King Sancho II (1223–1248 CE), decisively implemented administrative reforms and strengthened royal governance. León and Castile navigated complex diplomatic relationships under Alfonso IX of León (1188–1230 CE) and the young Ferdinand III of Castile (1217–1252 CE), significantly reshaping Iberian geopolitics. Navarre, governed by Sancho VII "the Strong" (1194–1234 CE), preserved diplomatic autonomy, internal governance stability, and territorial integrity amid shifting regional alliances.

Political and Military Developments

Portuguese Administrative Centralization under Afonso II

King Afonso II decisively strengthened royal governance, centralizing administration, codifying legal structures, and promoting efficient management of lands and resources. His reforms significantly reduced the power of feudal nobility, enhancing civic stability, legal coherence, and royal authority. Following his death in 1223, his son, Sancho II, inherited a centralized yet politically challenging kingdom, facing rising aristocratic tensions.

Diplomatic Realignments in León and Castile

León-Castile experienced significant political shifts. Alfonso IX of León and Ferdinand III of Castile (who inherited Castile in 1217) navigated complex diplomatic relations marked by initial rivalry and eventual rapprochement. Ferdinand III decisively strengthened Castilian territorial defenses and governance stability, setting the stage for future reunification with León. Alfonso IX continued effective frontier governance and maintained internal coherence despite diplomatic complexities, significantly reinforcing Leonese identity.

Navarre’s Diplomatic Stability under Sancho VII

Under Sancho VII "the Strong", Navarre maintained careful diplomatic neutrality, effectively balancing alliances with Castile, Aragón, and southern Muslim taifa states. His prudent diplomacy significantly preserved Navarrese regional autonomy, internal stability, and distinct civic identity amid broader Iberian geopolitical transformations.

Economic Developments

Robust Agricultural and Economic Prosperity

Agricultural productivity continued to thrive, decisively supported by advanced irrigation techniques and diverse crop cultivation (citrus, olives, almonds, vineyards, grains). Thriving mining operations (silver and gold from Galicia and Asturias) and livestock husbandry significantly supported economic resilience, population stability, and territorial consolidation.

Maritime Trade and Northern European Commerce

Portuguese ports, especially Lisbon, Porto, and Coimbra, significantly expanded maritime trade networks, reinforcing economic exchanges with northern Europe (England, Flanders, Normandy, Brittany). Galicia, notably through A Coruña, maintained dynamic maritime commerce, significantly bolstering regional economic autonomy and prosperity.

Pilgrimage-Driven Economic Vitality

Pilgrimage to Santiago de Compostela remained economically vibrant, decisively supporting hospitality industries, artisanal commerce, cultural exchanges, and economic resilience. Continued pilgrimage activity significantly reinforced Galicia’s economic prominence, cultural vitality, and regional identity.

Cultural and Religious Developments

Galician Cultural Resilience and Santiago’s Prestige

Galicia’s cultural vitality flourished, decisively reinforced by Santiago de Compostela’s international pilgrimage prominence. Ecclesiastical patronage significantly supported substantial architectural projects, scholarly pursuits, manuscript preservation, and educational initiatives, shaping Galician cultural identity and European-wide prestige.

Monastic Intellectual Activity and Ecclesiastical Influence

Monastic communities sustained active intellectual pursuits, manuscript production, educational initiatives, and agricultural innovations. Cluniac reforms and ecclesiastical discipline significantly shaped Iberian religious identity, liturgical uniformity, and regional cultural cohesion.

Persistent Cultural Syncretism and Local Traditions

Orthodox Christianity continued integrating indigenous Iberian and Celtic traditions, notably in rural Galicia and northern Portugal. Enduring cultural syncretism decisively reinforced distinct regional identities, social cohesion, and cultural resilience amid broader political transformations.

Civic Identity and Governance

Portuguese Centralization and Civic Stability

Under Afonso II and subsequently Sancho II, Portuguese governance significantly centralized, enhancing civic stability, territorial coherence, and legal administration. These administrative reforms significantly strengthened Portuguese national identity, territorial governance, and medieval civic structures.

Leónese and Castilian Civic Identity and Diplomatic Adaptation

Alfonso IX of León and Ferdinand III of Castile navigated diplomatic complexities while decisively reinforcing internal governance stability and distinct regional identities. Clearer definitions of Leonese and Castilian identities significantly reinforced regional governance coherence and Iberian political stability.

Navarre’s Governance Autonomy and Diplomatic Neutrality

Under Sancho VII, Navarre maintained resilient regional autonomy, governance stability, and diplomatic neutrality amid complex Iberian geopolitics. His prudent diplomatic strategies significantly preserved Navarre’s internal coherence, territorial integrity, and governance effectiveness.

Notable Regional Groups and Settlements

• Portuguese: Decisively solidified national sovereignty, territorial governance, and civic stability under Afonso II and Sancho II, significantly shaping Portuguese identity and enduring medieval coherence.

• Castilians and Leonese: Maintained clearly defined regional identities and governance stability, decisively reinforced by Alfonso IX and Ferdinand III through diplomatic adaptation and frontier governance.

• Galicians: Sustained cultural prominence and economic vitality, significantly supported by pilgrimage traditions, maritime commerce, and ecclesiastical patronage.

• Basques (Navarre): Maintained resilient regional autonomy, diplomatic neutrality, and internal governance stability under Sancho VII, decisively shaping northern Iberian geopolitics and regional stability.

Long-Term Significance and Legacy

Between 1216 and 1227 CE, Atlantic Southwest Europe:

• Achieved decisive administrative centralization, legal coherence, and national governance stability in Portugal under Afonso II and Sancho II, significantly influencing Portugal’s medieval identity and historical trajectory.

• Navigated diplomatic realignments, territorial governance stability, and clearly defined regional identities in León and Castile, significantly shaping Iberian political coherence and regional stability.

• Maintained careful diplomatic neutrality, governance autonomy, and regional identity coherence within Navarre under Sancho VII, decisively shaping northern Iberian geopolitical stability.

• Sustained economic prosperity, pilgrimage-driven cultural exchange, maritime commerce, and regional governance stability, significantly influencing Atlantic Southwest Europe’s enduring medieval historical trajectory.

This era decisively shaped administrative coherence, diplomatic alignments, territorial stability, and cultural resilience, profoundly influencing Atlantic Southwest Europe’s enduring medieval legacy.

Berengaria had yielded young King Henry I to a Castilian count under specific terms when a faction of Castilian nobles plotted to take control of her brother and his throne.

The count, however, had ignored his compact, and his autocratic manner has brought Castile to the brink of ruination and revolution.

At Henry’s accidental death in 1217, however, Berengaria, as royal heiress, becomes queen.

A few months later, she accedes to the wishes of her subjects and yields her rights of succession to her eighteen-year-old son by King Alfonso IX of León, who is unaware of these actions.

Berengaria’s son is declared King Ferdinand III of Castile on August 31, 1217.

Castile’s young new king immediately sets about subduing the towns supporting the monarchial Castilian count.

When Ferdinand’s father, King Alfonso IX of León, learns of his estranged wife Berengaria’s abdication in favor of her son, he invades Castile with the intention of unifying both kingdoms under his rule.

Finding scant support when the Castilian nobles flock instead to Ferdinand’s banner, he withdraws and reaches an amicable accord with his son, who retains the crown of Castile.

The Foundation of Burgos Cathedral (1221)

On July 20, 1221, King Ferdinand III of Castile and Mauricio, the English-born Bishop of Burgos, ordered the construction of the Cathedral of Burgos, a grand new structure inspired by the French Gothic style. The cathedral’s design was modeled after Bourges Cathedral, featuring a gigantic arcade and a relatively short clerestory, hallmarks of High Gothic architecture.

A Monument of Gothic Architecture

Construction commenced on the site of the former Romanesque cathedral, beginning with the chevet, which would be completed in just nine years. The new cathedral reflected the growing influence of French Gothic design in Iberia, marking a departure from earlier Romanesque traditions and signaling Castile’s cultural and political ties to European Christendom.

Over the coming centuries, Burgos Cathedral would continue to evolve, incorporating additional embellishments and architectural refinements, ultimately becoming one of Spain’s most iconic Gothic cathedrals.

John of Brienne—Stephanie of Armenia having died in 1219—weds Berengaria, daughter of Ferdinand III of Castile, in 1225.

At the urging of Pope Honorius III, John gives his daughter Isabella in marriage to Frederick II, as the Emperor's first wife, Constance, had died in 1222.

John tries to retain his rights as regent of the kingdom of Jerusalem but Frederick begins to contest these rights immediately following the marriage.

Pope Urban II had recognized Toldeo’s main church, a converted mosque, in 1088 as the primate cathedral over the rest of the kingdom.

The mosque-cathedral has remained intact until the thirteenth century, when in the year 1222 a Papal bull issued by the Pope had authorized the construction of a new cathedral which was begun in 1224 (or 1225).

The official ceremony of the laying of the foundation stone takes place in 1226 (other sources say 1227), with the presence of King Ferdinand.

The plan of the cathedral is directly modeled, like that at Burgos, on the scheme of the French Gothic Cathedral of Bourges.

Mediterranean Southwest Europe (1228–1239 CE): Reconquista Momentum, Imperial Struggles, and Mendicant Expansion

The era 1228–1239 CE in Mediterranean Southwest Europe is marked by significant Christian Reconquista gains in Iberia, ongoing political tension between Emperor Frederick II and the northern Italian communes, and continued growth and influence of the mendicant religious orders.

Reconquista Advances in Iberia

The Christian kingdoms of Iberia, particularly Castile, León, and Aragon, achieve notable territorial gains against the declining Almohad Caliphate. Ferdinand III of Castile and León, particularly active during this period, successfully captures key cities and fortresses, including important advances in Andalusia. This momentum significantly weakens Almohad power, paving the way for further Christian advances into southern Iberia.

Imperial Conflicts and Communal Resistance in Northern Italy

The northern Italian city-states, organized within the Lombard League, continue their resistance against Holy Roman Emperor Frederick II. Conflict escalates significantly as Frederick asserts imperial authority over the autonomous communes. Key cities such as Milan, Brescia, and Alessandria vigorously resist imperial control, reinforcing communal solidarity and autonomy through defensive alliances and political resilience.

Expansion of Dominican and Franciscan Orders

The Dominicans and Franciscans extend their presence across Europe, significantly shaping the religious, intellectual, and social landscape of the region. Both orders deepen their scholarly and pastoral activities, establishing universities, convents, and preaching missions in Italy, Iberia, and beyond. The influence of these mendicant orders continues to foster spiritual renewal, theological innovation, and social outreach.

Continued Cultural and Intellectual Exchange

The region sustains vibrant cultural and intellectual activity, particularly in the translation and dissemination of classical knowledge. Toledo remains a prominent scholarly hub, further facilitating translations from Arabic and Greek into Latin. These ongoing translations profoundly influence Western European thought, contributing to educational advancement and laying intellectual groundwork for future periods.

Maritime and Economic Vitality

Italian maritime republics, notably Venice and Genoa, maintain their economic prominence through sustained trade with Byzantium, the Levant, and North Africa. Their commercial dominance ensures continued economic prosperity and cultural exchange, reinforcing Mediterranean Southwest Europe's position as a crucial trade and cultural crossroads.

Legacy of the Era

The era 1228–1239 CE is significant for the accelerated Reconquista in Iberia, the vigorous assertion of communal autonomy against imperial pressure in northern Italy, and the expansive influence of the Dominican and Franciscan orders. Together, these developments significantly shape the religious, political, and cultural landscapes of Mediterranean Southwest Europe, influencing broader medieval and early modern transformations.