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  • Writer's picture@ Cynthia Adina Kirkwood

Portugal, U.K. to Celebrate World’s Oldest Alliance of 650 Years

Updated: Jun 19, 2022

PM Boris Johnson presented PM Antonio Costa with the original treaty at 10 Downing Street (Photo by Jornal de Noticias)


British Prime Minister Boris Johnson presented Portugal’s Prime Minister Antonio Costa with the original Treaty of Tagilde between the two countries, which began the world’s oldest diplomatic alliance.

Prime Minister Costa received the document, which had been removed temporarily from The National Archives, on his first visit to Prime Minister Boris Johnson’s official residence at 10 Downing Street in London on June 13, reported Noticias ao Minuto (June 13).

The treaty was signed on July 10, 1372, in the church of Sao Salvador of Tagilde, near Guimaraes, in the municipality of Vizela, by King Fernando I and representatives of John of Gaunt, the Duke of Lancaster, son of Edward III of England.

“Within a month, we will celebrate the 650th anniversary of the first treaty we signed with the United Kingdom,” Antonio Costa told journalists after his visit. “It remains the oldest alliance in the world.”

To highlight the longevity of the Portuguese-British alliance, Antonio Costa quoted his Minister of Foreign Affairs, Joao Gomes Cravinho, who was at his side:

“The Minister of Foreign Affairs usually says that the second oldest is NATO (The North Atlantic Treaty Organization is 73 years old). Therefore, take a good look at the distance and duration of the Portuguese-British alliance.”

Later, Antonio Costa said that, with Brexit (the United Kingdom’s exit from the European Union), the deepening of bilateral relations became essential, reported Noticias ao Minuto.

“In the years we were together in the European Union, bilateral relations were probably diluted in the collective space of the European Union. Now that Brexit is consolidated (January 31, 2020), and the COVID-19 pandemic is no longer a border and a barrier to travel in recent years, this is a great opportunity to relaunch and re-establish this bilateral relationship.”

England’s Treaties of Guarantee in The Law Magazine and Review (1881) cites a famous passage of the treaty that ensures the two nations' loyalty to each other:

“There shall be between the respective kings and their successors, their realms, lands, dominions, provinces, vassals, and subjects whomsoever, faithfully obeying, true, faithful, constant, mutual, and perpetual friendships, unions, alliances, and leagues of sincere affection; and that, as true and faithful princes, they shall henceforth reciprocally be friends to friends and enemies to enemies, and shall assist, maintain, and uphold each other mutually, by sea and by land, against all men that may live or die of whatever degree, station, rank, or condition they may be, and against their lands, realms, and dominions.”

The Treaty of Tagilde was the first of a series of agreements between the two countries. The following year in 1373, it was reinforced by the Treaty of Peace, Friendship and Alliance, signed in London, according to Noticias ao Minuto. In 1386, the Treaty of Windsor renewed the alliance and solidified it with the marriage of the King of Portugal, Joao I, to Philippa of Lancaster, who provided royal patronage for English commercial interests that sought to meet the Portuguese desire for cod and cloth in return for wine, cork, salt and oil shipped through the English warehouses at Porto. The marriage ushered in a generation of princes called the “Illustrious Generation” by the poet, Luis Vaz de Camoes. One of the couple’s nine children, Prince Henry, the Navigator, guided Portugal to the Age of Discovery and its early voyages.

The Portuguese-British Alliance has served both countries throughout their military histories, for example, influencing the participation of the United Kingdom in the Peninsular War (part of the Napoleonic Wars) and the establishment of an Anglo-American base in Portugal.

Iberian Union Interrupted Alliance

The alliance was interrupted by the Iberian Union from 1580 to 1640 when the monarchies of Portugal and Spain were in a dynastic union. The struggle of Queen Elizabeth I of England against Philip II of Spain placed Portugal and England on opposite sides of the Anglo-Spanish War and the Dutch-Portuguese War.

However, in 1640, England supported the House of Braganza in its successful replacement of the House of Hapsburg, celebrated in Portugal as the Day of Restoration of Independence on December 1.

18th-19th Centuries

Since then, there have been many key episodes in the resurrected Portuguese-British Alliance.

In the War of the Spanish Succession (1701-1714), triggered by the death of Charles II of Spain and the ensuing struggle for control of the Spanish Empire between his heirs, Philip of Anjou and Archduke Charles of Austria, France and Spain were on one side and, on the other, Portugal supported England, the Dutch Republic and the Holy Roman Empire.

After the Spanish invasion of Portugal (May 5-November 24, 1762), a military episode in the Seven Years’ War, Spain and France were defeated by the Portuguese-British Alliance with broad popular resistance.

During the Napoleonic Wars (1803-1815), Portugal, isolated in a Napoleon-dominated Europe, continued to trade with the United Kingdom despite French restrictions. Under escort by the British fleet, Queen Maria I, Prince Regent Joao, the Braganza royal family and the court of 420 people strategically embarked for Brazil on November 29, 1807, just days before Napoleonic forces invaded Lisbon on December 1.

(For 13 years, Rio de Janeiro functioned as the capital of the Kingdom of Portugal in what some historians call a metropolitan reversal in which a colony exercises governance over the entirety of an empire. The Portuguese crown remained in Brazil until the Liberal Revolution of 1820, demanding greater self-rule for the Portuguese, which led to the return of Joao VI to Portugal on April 26, 1821, according to 1808: The Flight of the Emperor (2007).

(Liberalism, in this context, is a political and moral philosophy based on the rights of the individual, liberty, consent of the governed and equality before the law, as defined by Concise Oxford Dictionary of Politics (2009).

Meanwhile, the British sent Lieutenant-General Sir Arthur Wellesley, later to be the 1st Duke of Wellington, to Portugal to lead a joint Portuguese-British force against Napoleon. Portugal regained total sovereignty.

In 1806-1807, the Portuguese helped the failed British invasions of the Rio de la Plata in the Spanish colony of what is today Argentina and Uruguay.

The death of King Joao VI in 1826 created a dispute over royal succession that resulted in the Liberal Wars, also known as the Portuguese Civil War (1828-1834), which pit liberal constitutionalists against conservative absolutists. The United Kingdom gave important support to the successful Liberal faction.

1890 British Ultimatum Soured Relations

With the 1890 British Ultimatum, under pressure from Cecil Rhodes, co-founder of De Beers Consolidated Mines (1888) and Prime Minister of the Cape Colony (present-day South Africa) (1890-1896), the British government demanded the withdrawal of Portuguese troops from Mashonaland and Matabeleland (both in present-day Zimbabwe) and the Shire-Nyasa region (present-day Malawi), where Portuguese and British interests overlapped in Africa, according to Lord Salisbury’s 1890 Ultimatum to Portugal and Anglo-Portuguese Relations (2006). Britain was claiming sovereignty over territories, some of which had been claimed as Portuguese for centuries. It demanded that Portugal refrain from colonizing land between the Portuguese colonies of Angola, on the west coast, and Mozambique, on the east coast.

Despite the popular uproar, Portugal acquiesced to British demands. The British Ultimatum was considered to be a breach of the Portuguese-British Alliance and a national humiliation by republicans, who denounced the government and King Carlos I as responsible for it, according to The Politics of Non-Translation: A Case Study in Anglo-Portuguese Relations in Ideology and Translation (2000). The government fell. The night after the ultimatum was accepted, Alfredo Keil composed the melody for the Portuguese national anthem, A Portuguesa.

The 1890 British Ultimatum soured Portuguese-British relations for some time. However, in the late 1890s when Portugal underwent a severe economic crisis, it sought a British loan. Also, with the outbreak of the Second Boer War (1899-1902), Britain sought support from Portugal and signed a Portuguese-British declaration on October 14, 1899. This new treaty reaffirmed former treaties of the Alliance. It committed Britain to defend Portuguese colonies from possible enemies, while Portugal agreed to stop arms being supplied to the Transvaal through Lourenço Marques (present-day Maputo, Mozambique) and declared its neutrality in the conflict, according to Lord Salisbury’s 1890 Ultimatum to Portugal and Anglo-Portuguese Relations (2006).

Nevertheless, the 1890 British Ultimatum was said to be one of the main causes for the Republican Revolution, which ended the monarchy in Portugal 20 years later (October 5, 1910), and the assassinations of King Carlos I and Crown Prince Luis Filipe (February 1, 1908).

20th Century

In World War I (1914-1918), after German incursions in Portuguese East Africa (present-day Mozambique), Portuguese troops supported British, South African and Belgian military operations there and in German East Africa, according to New Zealand History: Allies: Republic of Portugal.

Upon the declaration of World War II in September 1939, the Portuguese government announced on September 1 that the Portuguese-British Alliance remained intact. However, since the British did not seek Portuguese assistance, Portugal would remain neutral. In an aide-memoire of September 5, 1939, the British government confirmed the understanding. British strategists regarded Portuguese non-belligerency as “essential to keep Spain from entering the war on the side of the Axis”, according to Neutrality by Agreement: Portugal and the British Alliance in World War II, American University International Law Review (March 19, 2014).

Nevertheless, Prime Minister Antonio Oliveira Salazar provided aid to the Allies. In July 1940, Salazar allowed 2,500 Gibraltar evacuees to be shipped to Madeira, according to Madeira Gold Medal of Merit, Gibraltar Chronicle (January 9, 2013).

In a telegram to the British Foreign Office in 1943, the British ambassador to Portugal, Sir Ronald Hugh Campbell confirmed that the British government had invoked the 600-year-old alliance between the two countries as a basis for requesting the use of military facilities on the Azores, according to History’s Unparalleled Alliance: The Anglo-Portuguese Treaty of Windsor, 9th May 1386, History of British Government (May 9, 2016).

Salazar responded favorably and virtually at once, according to Salazar and Modern Portugal (1970). Portugal granted Britain the use of bases in the Azorean ports of Horta and Ponta Delgada, and airfields of Lajes Field on Terceira Island and Santana Field on Sao Miguel Island.

From November 1943, when the British gained the use of the Azores, to June 1945, cargo aircraft carried vital personnel and equipment to North Africa, the United Kingdom and, after the Allies gained a foothold in Western Europe, to Orly Field near Paris. Flights from Europe carried wounded soldiers. Medical personnel at Lajes Field handled approximately 30,000 air evacuations to the United States for medical care and rehabilitation. By using Lajes Field, flight time between the United States and North Africa was reduced from 70 hours to 40. Aircraft could make almost twice as many crossings per month, clearly demonstrating the strategic value of the Azores during World War II.

During the 1982 Falklands War, Portugal offered the facilities of the Azores to the Royal Navy, according to History’s Unparalleled Alliance: The Anglo-Portuguese Treaty of Windsor, 9th May 1386, History of British Government (May 9, 2016).

Back to the Present (2022)

Vitor Hugo Salgado, president of the municipality of Vizela, obtained a copy of the Treaty of Tagilde on a recent visit to London, reported Noticias ao Minuto (June 13).

In May, members of the “Portugal United Kingdom 650” commission presented a proposed program at Windsor Castle to Prince William and the British Minister of Defense, Ben Wallace, who attended the Royal Military Academy at Sandhurst, of events to commemorate the treaty’s 650th anniversary, reported Noticias ao Minuto.

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