The Peace of Alcoutim (1371): Ferdinand I Abandons His Claim to Castile

After his humiliating defeat in the First Fernandine War (1369–1371) against Henry II of Castile, King Ferdinand I of Portugal was forced to negotiate peace to prevent further destruction.

Terms of the Peace Treaty (1371)

• Ferdinand formally renounced his claim to the Castilian throne, abandoning his support for towns that had remained loyal to Peter I of Castile.
• Portugal agreed to pay reparations to Castile.
• To secure the peace, Ferdinand pledged to marry Henry II’s daughter, Leonor of Castile, creating a dynastic alliance between the two kingdoms.

Ferdinand’s Betrayal of the Treaty

Despite the treaty’s terms, Ferdinand soon broke his engagement to Leonor of Castile, choosing instead to marry Leonor Teles de Meneses, a Portuguese noblewoman of ambitious and controversial reputation.

• His abandonment of the arranged marriage infuriated Castile, further damaging relations between the two kingdoms.
• This betrayal renewed hostilities and contributed to the outbreak of the Second Fernandine War (1372–1373).
• The Portuguese nobility was divided, as many saw his decision as reckless and politically dangerous.

Consequences of the Peace of Alcoutim

• While it ended immediate warfare, the treaty failed to establish a lasting peace between Portugal and Castile.
• Ferdinand’s personal ambitions and disregard for diplomatic agreements kept Portugal embroiled in conflict, weakening its stability and draining its resources.
• These tensions would culminate in the Portuguese crisis of 1383–1385, a succession dispute that ultimately led to the rise of the House of Avis and the consolidation of Portuguese independence.

Thus, the Peace of Alcoutim (1371), though a temporary truce, did little to prevent further wars, betrayals, and political instability in Portugal’s relations with Castile.