THE ANGLO-PORTUGUESE ALLIANCE WAS ESTABLISHED 648 YEARS AGO

 

The Anglo-Portuguese alliance was born out of converging strategic interests: An alliance between France and Castile in 1369 had caused great concern at the English court. Through the alliance with Castile, which had one of the largest fleets in Western Europe, France had access to Castilian sea power. Therefore closer union with Castile’s western neighbor Portugal was a logical step to counter this threat. 

 

Added to this was a dynastic interest as the Duke of Lancaster, John of Gaunt, had a legitimate claim to the throne of Castile through his wife, Constance, daughter of Pedro I (1334-1369). With military victory in the Iberian Peninsula and a Plantagenet on the Castilian throne, it would only be a matter of time before France would be forced to the negotiating table. 

 

The treaty was signed on June 16, 1373 between King Edward III of England and King Fernando and Queen Leonor of Portugal. It established a treaty of "perpetual friendships, unions [and] alliances" between the two nations. 

Battle of Aljubarrota from A Batalha graphic novel by Pedro Massano, 2014.

 

In the aftermath, England sent a failed expedition to Portugal in 1381-2 under Edmund of Langley in an attempt to push Castile out of the war. Undisciplined English troops caused outrage by raiding Portuguese towns and killing inhabitants whilst exclusion from Portuguese-Castilian peace negotiations in 1382 drew English resentment. 

 

After the death of King Fernando I, Joao of Aviz sent ambassadors to England to request permission to recruit mercenaries. The Portuguese ambassador Fernando Afonso de Albuquerque, Master of the Portuguese military order of Sant'Iago da Espada succeeded initially in raising only a modest force of approximately 800 Anglo-Gascon troops. Nevertheless these soldiers would play a laudable role in the eventual defeat and withdrawal of Castilian forces from Portugal particularly with their contribution to the victory over Castilian troops at the battle of Aljubarrota (14th August 1385). 

Treaty of alliance between king Edward III of England and Fernando I of Portugal, 16th June 1373 (British National Archives: E 30-275)

Joao I was recognized as the undisputed King of Portugal, putting an end to the interregnum of the 1383–1385 Crisis. The Treaty of Windsor in 1386 established a pact of mutual support between the countries.

 

Although not invoked until several centuries later, the terms of the alliance were to be called upon during the 18th and 19th centuries when Portuguese independence was again threatened. In 1762 Anglo-Portuguese forces successfully defeated a Spanish invasion force and again during the Peninsula war of 1808-1814, Anglo-Portuguese troops under the Duke of Wellington thwarted Napoleon’s attempts to conquer Portugal, most notably at the battle of Buçaco (27 September 1810) which allowed Viscount Wellington and Portuguese General Luís do Rego Barreto to resume the retreat of their 52,000 men into the previously fortified Lines of Torres Vedras, a contiguous line of fortifications extending from the Tagus River to the ocean.  

Brigadier-General Robert Craufurd and the 52nd at Buçaco, 27th September 1810 by Christa Hook. The Royal Green Jackets Museum, Winchester.