Portugal:

• Under King Duarte I (r. 1433–1438), Portugal continued maritime exploration initiated by João I and Prince Henry the Navigator, despite Duarte’s short reign and internal divisions following his death.
• Duarte’s premature death triggered a regency crisis, with his brother, Infante Pedro, Duke of Coimbra, serving as regent (1439–1448), reinforcing Portugal’s commitment to exploration and internal reform.

Northern Castile and León:

• King Juan II of Castile (r. 1406–1454) faced growing conflict between powerful nobles, notably between the factions led by Álvaro de Luna and the Infantes of Aragón, significantly impacting political stability in the northern provinces.
• The Basque territories and northern Rioja capitalized on Castilian internal strife to preserve local autonomy, solidifying their distinctive fueros and customs.

Navarre:

• Queen Blanche I of Navarre (r. 1425–1441) continued her father’s diplomatic neutrality but faced rising pressure from Castile and Aragón. Her death in 1441 led to a succession crisis, ultimately resolved by the ascension of her son, Charles, Prince of Viana, whose contested rule invited further regional instability.

Portuguese Maritime Leadership:

• Continued expeditions along the African coast resulted in increased trade, particularly in gold and slaves, enriching coastal cities like Lisbon and Porto and fostering an emerging Atlantic economic system.
• Settlement and cultivation in Madeira expanded significantly, becoming a prosperous source of sugar and Madeira wine, thereby enhancing Portugal’s Atlantic trade dominance.

Trade and Urban Prosperity:

• Northern coastal cities, including Bilbao and Santander, maintained flourishing trade with England, France, and the Low Countries, ensuring regional economic prosperity despite Castilian internal tensions.
• The Basque fishing and shipbuilding industries expanded, driven by robust international demand and increased maritime activity.

Humanism and Renaissance Influence:

• Portuguese scholars, sponsored by Infante Pedro and Prince Henry, continued developing maritime science, navigation techniques, and cartography, significantly contributing to Europe's growing intellectual and scientific heritage.
• Literary and humanistic influences from Italy and France permeated the courts of Portugal and Navarre, stimulating cultural refinement.

Local Autonomy and Identity:

• Northern Navarre, the Basque Country, and northern Rioja reinforced regional identities and fueros in response to broader political uncertainties, enhancing cultural resilience.
• Galicia and Asturias sustained vibrant pilgrimage traditions and cultural exchanges around Santiago de Compostela, preserving their importance as cultural hubs.

Portugal:

• Under regent Infante Pedro, Duke of Coimbra (1439–1448), maritime exploration expanded significantly, culminating in expeditions past Cape Verde (1444) and establishing Portugal’s claim over African coastal trade routes.
• After a brief civil conflict, King Afonso V (r. 1438–1481) ended Pedro’s regency violently in 1449, shifting Portugal’s internal politics toward increased royal centralization and expansionist ambitions.

Northern Castile and León:

• Ongoing instability under King Juan II of Castile (r. 1406–1454) intensified due to the influential minister Álvaro de Luna’s controversial control, leading to escalating feuds among noble factions and weakening royal authority in northern provinces.
• The execution of Álvaro de Luna (1453) brought temporary calm, yet political fragmentation persisted, allowing greater regional autonomy in territories such as Galicia, Asturias, and the Basque Country.

Navarre:

• Succession crises intensified under Charles, Prince of Viana, whose disputed inheritance after Queen Blanche’s death (1441) drew Navarre into deeper conflict, particularly with the ambitions of John II of Aragon, destabilizing governance and increasing external interference in Navarrese politics.

Portuguese Trade Networks:

• Portuguese expeditions along West Africa’s coast led to significant economic gains from gold, ivory, and slave trade, consolidating Lisbon as a thriving Atlantic port and financial hub.
• Madeira’s sugar plantations, established in prior decades, matured into prosperous enterprises, significantly influencing future patterns of plantation agriculture and Atlantic commerce.

Urban and Commercial Vitality:

• Atlantic ports in northern Iberia, notably Bilbao and Santander, benefited from trade stability, especially with northern Europe, strengthening their economic standing despite Castilian political fragmentation.
• Basque maritime traditions flourished through shipbuilding and fisheries, reinforcing the region’s economic independence and international trade connections.

Intellectual Growth and Humanism:

• Portuguese courts embraced Renaissance humanism and maritime innovation, sponsoring mapmakers, astronomers, and navigators such as Diogo Gomes and Alvise Cadamosto, whose work refined Europe’s geographic knowledge.
• Cultural exchanges through pilgrimage routes to Santiago de Compostela continued to foster literary and scholarly interactions across the Pyrenean territories.

Regional Identity and Autonomy:

• Basque territories and northern Navarre reinforced traditional legal privileges (fueros), promoting distinctive regional identities and autonomy amid Castile’s internal struggles.
• Galicia and Asturias preserved vibrant local cultures, resisting centralized pressures through the strength of traditional communal institutions and networks centered around religious and cultural hubs.