The Beginnings of the Anglo-Portuguese Alliance

The formal beginning of the Anglo-Portuguese alliance, the oldest diplomatic alliance still in force, dates back to the second half of the fourteenth century. The Anglo-Portuguese friendship is even older and dates back at least to the twelfth century. Also dating from the twelfth century is a well-known episode during the Second Crusade. In 1147 a group of crusaders on their way to the Holy Land from England and Northern Europe stopped at the port in the city of Oporto and helped D. Afonso Henriques reconquer Lisbon(1). Afterwards, most of the crusaders proceeded to the Holy Land, but a group of Englishmen remained in Portugal, among them Gilbert de Hastings, the new Bishop of Lisbon. 

Since this episode, the friendship between Portugal and England developed steadily through periods of greater and lesser proximity. This friendship can be attested by two letters, dated June 1199, in which John, King of England, refers to the King of Portugal as karissimi fratis nostri & amici Regis Portigalen and awards the highest honors to the ambassadors of Portugal(2). Trade relations were reinforced by the 1352 Anglo-Portuguese treaty signed between King Edward III and Afonso Martins Alho, the latter representing merchants and sailors of Portugal. 

It was in the second half of the fourteenth century that relations between both countries gained greater stability. The legal foundations of the Anglo-Portuguese alliance are found in three treaties dating from that period: the Treaty of Tagilde (10 July 1372), the Treaty of London (16 June 1373), and the Treaty of Windsor (9 May 1386).

Treaty of Tagilde 

Treaty of Tagilde, 1372. Duchy copyright material in The National Archives is the property of Her Majesty The Queen in Right of Her Duchy of Lancaster and is reproduced by permission of the Chancellor and Council of the Duchy of Lancaster.


The Treaty of Tagilde(3), signed by D. Ferdinand I of Portugal and the representatives of John of Gaunt, Duke of Lancaster and son of Edward III of England, on 10 July 1372 is considered the preamble of the alliance that still prevails today(4). This treaty, signed at the Church of São Salvador of Tagilde (Vizela municipality, Braga district), sealed the alliance of the two claimants to the Castilian throne.

The context of the Treaty of Tagilde was the Hundred Years’ War and the disputes over the Castilian throne between two brothers. D. Pedro, who had been stripped of the Castilian crown by D. Enrique de Trastámara, his illegitimate brother, gained English support to recover it from D. Enrique, who had the support of France. At the battle of Montiel (1369), D. Pedro was killed and D. Ferdinand I of Portugal, the legitimate great-grandson of D. Sancho IV of Castile, declared war on D. Enrique.

It was under these circumstances that an embassy arrived in Portugal from John of Gaunt, Duke of Lancaster, among whose ambassadors were João Fernandes Andeiro and Roger Hoor. The Duke of Lancaster had married D. Pedro’s daughter Constance in 1371 and therefore had pretensions to the Castilian throne. The ensuing Treaty of Tagilde determined that the King of Portugal and the Duke of Lancaster were true friends and that they would wage simultaneous war against Castile and Aragon on two fronts: the English on the north and the Portuguese on the west(5).

D.Ferdinand, shortly after signing the Treaty, sent two ambassadors, Vasco Domingues and João Fernandes Andeiro, to the Duke of Lancaster in England to swear and sign the Treaty of Tagilde(6), which they duly did at the Savoy Palace(7). These ambassadors also carried powers to make complementary alliances with King Edward III of England and the Prince of Wales(8). These negotiations resulted in the Treaty of London of 16 June 1373.

Dom Fernando, King of Portugal, and Queen Eleanor to  John of Gaunt, Duke of Lancaster, requiring the confirmation of the Treaty of Tagilde, November 1372. 

Duchy copyright material in The National Archives is the property of Her Majesty The Queen in Right of Her Duchy of Lancaster and is reproduced by permission of the Chancellor and Council of the Duchy of Lancaster.



Treaty of London

The Treaty of Peace, Friendship and Alliance between King Ferdinand I and Queen Leonor of Portugal and King Edward III of England was agreed in perpetuity on 16 June 1373 at St. Paul’s Cathedral(9). It is considered the main legal foundation of the Anglo-Portuguese alliance and quotes the Treaty of Tagilde as its precedent, while presenting itself as an extension of those clauses(10). Its four clauses include the declaration of mutual and perpetual peace, friendship, union and alliance between the two parties, the commitment by both parties not to establish friendship with the enemies and persecutors of the other party, and the reciprocal obligation of assistance with military aid, or any other type of aid, for the need to defend the kingdom, provinces, dominions and places in the event of offence, oppression or invasion by land or sea. This treaty, with no revisions, has subsequently been confirmed on several occasions(11).


Treaty of Windsor 

Treaty of Windsor, 1386 © Crown copyright. Licensed under the Open Government Licence v3.0. (

On 9 May 1386, the Treaty of Windsor between John I of Portugal and Richard II of England was signed in perpetuity, ratifying the ‘perpetual league, friendship and confederation’ between the two monarchs, with the obligation of mutual aid(12). This treaty has greater breadth of content than the two previous treaties, as it enshrines in its articles the freedom of trade and transit for natives of each party in the territory of the other party ‘as if they were its natives’(13).

One of the first practical consequences of this treaty was to propitiate the beginning of diplomatic negotiations for the marriage between D. John I of Portugal and Philippa of Lancaster, daughter of John of Gaunt. The marriage took place on 2 February 1387 and initiated a period of greater proximity between the two reigning houses(14). The alliance became even closer when the son of John of Gaunt, who was also brother-in-law of King John I of Portugal, became Henry IV of England. 

Santarém tells us that England’s alliance with Portugal was so close from the last half of the twelfth century to the end of the fifteenth century that in the sixteen treaties which English sovereigns concluded with other nations, Portugal was always included as England’s ally and confederate(15). The fact that John I of Portugal was the first foreign monarch to become Knight of the Garter (1400) supports the claims of those who see the Kingdom of Portugal as England’s first political ally(16).

The Wars of the Roses initiated a new period in the parties’ relationship. However, the pact of ‘true, faithful, constant, mutual, and perpetual friendships, unions, alliances, and deeds of sincere affection’ described in Article I of the Treaty of London has continued. In fact, since then the alliance has been embodied in a considerable range of Anglo-Portuguese treaties and confirmed on successive occasions, the last formal one in 1914.

With the benefit of hindsight, we agree with the affirmation of English historian Richard Lodge who said ‘there is no state in Europe with which our relations have been on the whole so continuously intimate and friendly’(17) and also with Winston Churchill who described the alliance as one ‘without parallel in world history’(18). During more than six centuries of its existence, the Anglo-Portuguese alliance has survived the most challenging of historical contingencies, including two world wars, the rise and fall of empires, revolution and decolonisation, the multilateralization of international relations, European integration and the end of the Cold War. Today, in a context shaped by Brexit, we hope this alliance continues to inspire new chapters of friendship that will be celebrated for another 650 years.


Author of the text:

Alexandra M. Rodrigues Araújo (2020), Doctor Integrated Researcher at the Research Centre for Justice and Governance, University of Minho.

This article was financed by national funds through the National Agency for Science and Technology, FCT (Fundação para a Ciência e a Tecnologia – FCT I.P.), under the project Ref. UID/05749/2020.



1 The traditional version of this episode reports that the aid provided was a matter of chance: when the crusaders’ vessels landed for refueling in the city of Oporto, the Bishop of that city went to receive them and persuaded their leaders to help D. Afonso Henriques. A more recent version, based on a letter from Bernard of Clairvaux to D. Afonso Henriques, argues that this stop in Portugal was encouraged and planned in advance by the famous prelate. This would explain, among other aspects, the reason why this group decided to use the sea route to reach Palestine, while the majority of the crusaders who made up the Second Crusade travelled by land. Cf. J. Phillips, St. Bernard of Clairvaux, the Law Countries and the Lisbon letter of the second crusade, [Journal of Ecclesiastical History, 48], Cambridge 1997, p. 485-497; H. Livermore, The Conquest of Lisbon and its author, [Portuguese Studies, 6], 1990, p. 1-16.

2 Cf. T. Rymer, Foedera, Conventiones, Litterae, Et Cujuscunque Generis Acta Publica, Inter Reges Angliae Et Alios Quosvis Impeatores, Reges, Pontifices, Principes, Vel Communitates: Ab Ingressu Gulielmi I. In Angliam, A.D. 1066, Ad Nostra Usque Tempora Habita Aut Tractata, Record Commission Edition, T. I, London 1641-1713, p. 76.

3 The National Archives (TNA): DL34/1/30.

4 Cf. S. Pinto, Tratado de Tagilde de 10 de julho de 1372, [Scientia Iuridica, Separata, Year II, 6], Braga 1952, p. 1-18.

5 Cf. P. E. Russell, A intervenção Inglesa na Península Ibérica durante a guerra dos cem anos, Lisboa 1955. pp. 221-222.

6 Cf. TNA: DL34/1/29.

7 Cf. Pinto, Tratado de Tagilde (supra, n. 4), p. 10-11.

8 Santarém, Quadro elementar das relações políticas e diplomáticas de Portugal com as diversas potencias do mundo: desde ó princípio da monarchia portugueza até aos nossos, v. XIV, Lisboa 1842, p. 55. 

9 TNA: E30/275.

10 Cf. M. Caetano, Aliança Inglesa, [Enciclopédia Luso-Brasileira de Cultura 1], Lisboa 1963, p. 1262.

11 Cf. Statement by Mr Anthony Nutting in the House of Commons on 12 May 1952, Anglo-Portuguese Treaty, 1373: 12 May 1952: House of Commons debates – TheyWorkForYou

12 TNA: E30/310.

13 The Anglo-Portuguese treaty of 20 October 1353 already enshrined this clause of free transit for people and goods. However, this agreement was valid for only 50 years. Cf. T. Viúla de Faria and F. Miranda, Pur Bonne Alliance et Amiste Faire: Diplomacia e Comércio entre Portugal e Inglaterra no final da Idade Média, [Cultura, Espaço & Memória 1], Porto 2010, p. 111.

14 Cf. H. Baquero Moreno, O Tratado de Windsor de 1386 no conspecto das relações Luso-Inglesas, [Coloquio Comemorativo do VI Centenário do Tratado de Windsor], Porto 1988, p. 216-217.

15 Cf. Santarém, Quadro elementar das relações políticas e diplomáticas de Portugal com as diversas potencias do mundo: desde ó princípio da monarchia portugueza até aos nossos, V. XIV, 2.ª ed., Lisboa 1865, p. CXLIII.

16 Cf. V. Shillington and A. Chapman, The Commercial relations of England and Portugal, London 1907, pp. 18-19.

17  R. Lodge, The English factory at Lisbon: some chapters of its history, [Transactions of the Royal Historical Society 16] London 1933 p. 211.

18 Cf. Speech, House of Commons Debate, 12 October 1943 



Treaty of Peace, Friendship, and Alliance between England and Portugal, London 16 June 1373

Treaty of Alliance, 1373. © Crown copyright. Licensed under the Open Government Licence v3.0 (


Treaty of Peace, Friendship, and Alliance between England and Portugal. Signed at London 16 June 1373:

To all those who will see the content of the present page, William, Lord of Latimer,[1] Knight and Baron and Chamberlain of the Household, and Thomas Iuvenis [Young or Youngman], Official of the Court of Canterbury, proctors and negotiators of our most illustrious Prince and most dread lord, Lord Edward, by the Grace of God, King of England and France, specially deputed for the business written here, Greeting in the Lord in all events and in whatever times, and if it pleases you, to place firm credence in these presents.

Since the noble man João Fernandes de Andeiro, knight, and the venerable and discreet man Sir Velasco Domingo, Precentor of the church of Braga, ambassadors, proctors and special messengers on behalf of the illustrious and magnificent Prince, the Lord Ferdinand, by the grace of God King of Portugal and the Algarve and the most illustrious lady Lady Eleanor, his Queen and Consort, lately coming in person into the presence of our abovesaid Lord the King, in order to manifest the alliances, unions, confederacies, and leagues of pure affection reciprocally entered into, contracted and ordained, between the said King of Portugal and the Queen, and the Illustrious and Magnificent Prince, the Lord John, by the grace of God King of Castile and Leon, Duke of Lancaster, the very dear Son of our said Lord the King of England, and the sentiments of sincere affection derived not only thence but from the bonds of near consanguinity and the ancient friendship between them and their ancestors, of revered memory, which affection the said Lord King and Queen of Portugal had cherished, and would ever cherish, from their hearts, as well towards the person of the said Lord our King, as towards his Sons, and their rights and subjects, ardently wishing their welfare and honour, and desirous to make a firm stand against the malice of their Enemies, and the fraudulent machinations or designs wickedly conceived against the aforesaid Lord our King, his sons, realm, dominions, lands and subjects, as also cordially solicitous to enter into, contract, and unite in friendships, alliances, unions, good confederacies, and leagues of pure love, with our Lord the King himself, and with his first-born son, the Lord Edward, Prince of Wales, and with the other sons of the same Lord our King (with whom they had not yet formed any alliances), with the kingdom of England, and all his future successors whomsoever in the said Kingdom of England; and with the other lands, dominions, or places, and his faithfully obedient vassals and subjects, against all men that may live or die, and of whatever station, condition, rank, or dignity they may be, their kingdoms, dominions, lands, and provinces (only with special reservation of preserving intact and inviolate the state of the Apostolic See, and of our Lord the Pope), all which they most courteously stated, not only by word of mouth, but also publicly presenting letters of the aforesaid Lord the King and the Lady Queen, his Consort,  also by producing a public instrument of a certain proctor, authenticated with the seals of the said King and Queen, containing a power bestowed upon and granted them by the same King and Queen, of entering into, contracting, confirming, and reinforcing with due strength the said alliances, for and in the names of their aforesaid Masters, with the addition of such articles, stipulations, agreements, conditions, and clauses as they shall deem expedient to either party, their realms, lands, provinces, dominions, and subjects, just as any person looking at the tenor of the said instrument may more clearly and more fully understand; repeatedly praying our said Lord the King to declare, express, and intimate to them his gracious will and pleasure relative to the preceding matters. Thereupon, our Lord the King, having kindly seen and willingly heard all and each of the preceding subjects as proposed and presented by the same, and having diligently pondered and duly considered them, did within himself maturely reflect, how noble and how worthy of a King it would be to requite this sincere Royal affection thus spontaneously and most liberally proferred, by not only properly extolling and returning thanks for it, but by displaying similar or even greater good will; and what a safeguard and unfailing help in arduous and disastrous times, and how glorious in prosperity it is for Kings and the rulers of principalities to be mutually connected by alliances, unions, and leagues of pure affection. Inasmuch as, by their means, the prosperity and glory of Princes and Realms, after being raised to the highest pitch, are preserved in happy tranquillity, the welfare and safety of the subjects promoted, the malignity and perverse machinations of enemies frequently held in check, and, finally, numerous darts of dangers are met and anticipated by the sharing of counsel and aid, lest they wound unexpectedly, as may most clearly be learned from the crises of past times and from experience, that efficacious instructor; and after maturely deliberating on these matters with the prelates and nobles of his kingdom, did, with and of their common consent, appoint us, the before-mentioned William and Thomas, to be his true and lawful proctors, negotiators and the organ of his voice, just as is more amply set out in the Letters Patent of Attorney, made out accordingly, and sealed with his Great Royal Seal (whose beginning and conclusion are recited hereinafter) to the end that we should, in his stead and name, as well as in those of his kingdom of England and his Successors in the said kingdom, of its lands, dominions, provinces, and of all his faithfully obedient vassals and subjects whomsoever, contract, ordain, conclude, and validate with sufficient security, alliances, friendships, unions, good confederacies, and leagues of pure affection, with the aforementioned noble man Sir João Fernandes, Knight, and the venerable and discreet man Velasco Domingo, Precentor of the church of Braga, proctors and messengers of the aforesaid King and Queen, specially deputed for that purpose, in the places and names of the same, as also of those of the kingdoms of Portugal and the Algarve, the lands, dominions, vassals, and all other Subjects whomsoever faithfully obeying the said King of Portugal, with the addition and insertion of the clauses, articles, stipulations, agreements, and conditions which we shall, at any future times whatsoever, for purposes of utility, prosperity, and honour, deem expedient to either party and their successors, realms, lands, dominions, provinces, vassals and subjects as aforesaid.

We, on our part, anxious strictly to obey the Royal Orders of our aforesaid Liege Lord, from due faithfulness, and duly to execute what in this respect belongs to our office, in virtue of the power conferred upon us to this effect, and of the office which we have assumed, after sufficient deliberation, contract, ordain, make and establish with the foresaid Ambassadors, and with their express consent, in lieu and in the names of the persons before stated, in manner and form hereinafter set forth, alliances, confederacies, friendships, unions, and leagues of sincere affection, which shall for all time, the Most High willing, inviolably be observed.

[I]. Firstly, we ordain and agree that there shall be from this day forward between our foresaid Lord Edward, King of England and France, and the Lord Ferdinand King of Portugal and the Algarve, and the Lady Eleanor, Queen and his consort, their successors in the aforesaid kingdoms of England and Portugal, and their realms, lands, dominions, provinces, and all their vassals and subjects faithfully obeying them, true, faithful, constant, mutual, and perpetual friendships, unions, alliances, and leagues of sincere affection, and that just as faithful and true friends, they shall henceforth reciprocally be friends to friends, and enemies to enemies, and shall assist, maintain, and uphold each other mutually by land and by sea against all men who may live or die, of whatever dignity, station, pre-eminence, or condition they may be, and against their lands, realms, and dominions.

They shall strive for and preserve, as much as in them lies, the personal safety, security, interest, and honour, and the immunity, conservation and restitution of their rights, goods, effects, and friends, wheresoever they be.

They shall everywhere faithfully oppose the hurts and injuries, disgrace or, as we shall say, villainy, which they know or which one party knows to be at any future time threatened to the other party or contemplated against the other party, and shall provide remedies for them from henceforth; and they shall as expeditiously as may be, by letters or messengers, or in any other better way which they can contrive, wholly and fully inform, forewarn, and usefully counsel the other Party against whom such things are being machinated, on such matters.

[II]. Also, neither party shall form friendships with the enemies, rivals or persecutors of the other party; or knowingly himself or personally or through others advise, aid or favour the same enemies, rivals or persecutors of the other party, to his detriment, hurt or prejudice; encouraging the same in any way, receiving them into his kingdom or kingdoms, lands, dominions, provinces or places, or knowingly suffering them to be encouraged, received, sustained or harboured, either publicly or privately under any specious excuses, on any occasion or pretext whatsoever; not, however, including under the denomination of enemies, rivals or persecutors, such as shall now or hereafter for any reason or cause whatsoever have fled, been exiled, or banished from the kingdom, or from the other provinces, lands, dominions or places of either of the same kings, but, on the contrary, they may freely and reciprocally receive, maintain and support such persons in the kingdom, and in any lands and places subjected to the other king, unless indeed such fugitives, exiles and outlaws shall have been condemned by sentence of the crime of Lèse-majesté [High Treason], and as traitors to the king and the kingdom, or shall lie under the suspicion of having afforded occasion for reasonable fear of their design to compass the hurt, disgrace, injury or discord of both parties or of either of them, so that they ought to be justly avoided as foes and persecutors; in which case either party, on being required by the other, shall be obliged either to deliver up such men as aforesaid, if demanded, to the requiring party, or to expel, banish or dismiss them from his vicinity, his kingdoms, dominions and lands.

[III]. Item, if it happens that the kingdom, lands, dominions or places of the other party should be violated, oppressed, or invaded by land or by sea by enemies, persecutors or rivals, or if the same enemies should at least purpose, machinate, or in any manner propose to violate, oppress or invade, and the other party, or his successors, be through that party against whom such attempts are being machinated, by letters or by trusty messengers applied to for assistance or succour to be given and provided in men at arms, archers, crossbowmen, ships, galleys sufficiently prepared for war, or any other kind of defence whatsoever (provided such defence, or any of those before mentioned, exist or be used in the kingdom of which the above succour is demanded), then shall the said party so required furnish, supply and send the said succour in good faith to the requiring party as often and whenever the said party should require such for the defence of the realm against which such invasions are being prepared, or of the other provinces, dominions or places, and for the recovery of depredations by the like invasions, against the said enemies, invaders or persecutors, or against such as intend to invade or persecute, of whatever status, condition, pre-eminence and dignity they may be, according to the number and limit of men at arms, archers, crossbowmen, ships and galleys sufficiently supplied for war with all requisites and other kinds of defence which it can send or sustain without grave prejudice (always excepting when their price is excessive or they are needed in the country), at the cost, expense and pay of the party requiring, which is to be finely judged by four experienced soldiers or suitable and discreet members of the legal profession (of whom two are to be deputed or chosen by each party) according to the quality of the individuals to be sent, and their grades, to the circumstances of the times, and to the arena of the places in which the persons dispatched shall have to exert their valour or military skill, within such time as, after the aforesaid requisition, such succour ought to be prepared and sent, regard being had both to the pressing occasion of the party requiring, and to the possibility of the party called upon being able to complete his preparations, in all these proceedings, there being no duplicity or ill-will, but that the course of equitable dealing shall be pursued in a friendly manner.

Item, to the end that the above, collectively and singly, may effectively be fulfilled and faithfully observed, we the aforesaid proctors, in lieu and in the names of those above mentioned, promise in good faith and swear on the soul of our said Lord the King of England by touching the Holy Gospels, that he, our Lord the King, will with all his might and senses keep, fulfil, and inviolably observe, in whole and in part, the above-written alliances, friendships, unions, confederacies, and conventions, and their the articles and clauses whatsoever (always excepting alliances contracted beforehand), will cause them to be kept, fulfilled, and inviolably observed, and will neither ever transgress at any future time nor knowingly suffer to be in any way transgressed the above stipulations, or any of them, in whole or in part, by breaking, infringing or violating them knowingly, or by causing or suffering them to be infringed, violated, or broken, on pretence of any excuse, pretext or exception, fraud or deceit, error, coercion, written law, custom, act or intention, or privilege obtained or to be obtained, or of any machination of fraud, deceit or ill-will, in deed or word.

The tenor of our proctor’s warrant, of which mention has been made above, begins thus:

Edward, by the grace of God, King of France and England, Lord of Ireland, notify to all that we, reposing great confidence in the fidelity, circumspection, and industry of our beloved and trusty William, Lord of Latimer, our Councillor, and of Master Thomas Iuvenis [Young or Youngman], Official of the Court of Canterbury, make, constitute, and also appoint the same William and Thomas, together, and either of them, for himself (so that he who commences the transaction of any business shall not be entitled to superiority, but that what one of them begins the other shall be competent to continue, carry on, and finish), to be our proctors and negotiators, giving and granting to our said proctors, and to either of them, full and free power to treat and negotiate with the magnificent and illustrious Prince, the Lord Ferdinand, by the grace of God King of Portugal and the Algarve, and with the illustrious lady, the Lady Queen Eleanor, his consort, and their successors in their realms, lands and dominions of Portugal and the Algarve or with their proctors, ambassadors and messengers good and due alliances, unions and confederations against all persons and of whatever position, religion, dignity, station and condition existing, and their realms, lands and dominions and any of them, with those treaties, conditions, confederations, alliances, unions, conventions and pacts which our same proctors or either of them shall think should be made for our service and honour and the usefulness, keeping and defence of our realms, lands and dominions reserving however the good state of our Lord the Pope and the Roman church and in the same treaties, confederations, pacts, alliances, unions and conventions and conditions between us and the said King and Queen of Portugal and all others, successors of the same King and Queen in the foresaid realms or with their proctors by our said proctors and either of them, treated, ordained and held, agreeing and consenting that the same treaties, pacts, confederations, alliances, unions, conventions and conditions thus by them or by either of them agreed, ordained, held, with all their conditions in our name and the name of our successors should be established et cetera and thus it concludes.

In faith and witness of all which we have commanded our present letters to be made and we have ordered them to be authenticated by the appendance of our great seal. Given in our Palace of Westminster on the first day of the month of June in the one thousandth, three hundredth and seventy-third year of Our Lord and of our reigns the thirty-fourth of France and of England, the forty-seventh In faith and testimony of all which we have caused our present Letters to be made and published by Master John de Branketre [Braintree], the underwritten Notary Public and Royal Clerk, and to be authenticated by the appendance of our Seals.

Given and acted in the Royal City of London, at the Greater Cathedral Church there, on the feast of the New Solemnity of Corpus Christi; that is to say, on the 16th day of the month of June, in the one thousandth, three hundredth and seventy-third year of our Lord [1373], of the 11th Indiction and of the third year of the Pontificate of the Lord Pope Gregory the XIth.

In the presence of the noble men

Sir John Knyvet, Chancellor of England;

Sir Nicholas Carreu [Carew], Keeper of the King’s Privy Seal;

Sir John Gotery [Juan Gutiérrez], Dean of the Church of Segovia;

Thomas Orgrave, Archdeacon of Cornwall, in the church of Exeter;

Roger Holme,

Walter de Aldebury [Alderbury], and

William de Dyghton [Dighton], Canons of the said Greater Cathedral of London;

Nicholas de Tamworth, knight

Mathew Redmane, knight;

Master Simon de Multon, Doctor of Laws; and

Peter Didaci [Pedro Diogo], Knight Commander of the Order of Saint James in Portugal,

Witnesses to all the above said matters.

I, John de Branketre [Braintree], Clerk of Norwich Diocese, Notary Public by Apostolic and Imperial authority, and Secretary of the same Lord our King, because I was present along with the aforesaid witnesses at the alliances, contracts, taking of oaths, appendence of seals, and all and singular of the rest of the matters had, made, and performed by the above-named proctors, in the year, indiction, pontificate, month, day, and place hereinbefore noticed, and saw and heard all and singular of these matters to be so done, I have, on account of my being occupied with other Royal concerns, caused them to be put down in writing by another person, and have published and recorded them in the form of this public instrument, and have confirmed it with my usual notarial mark and name, in faith and testimony of the truth.

[1] Usually named William, Lord Latimer.


Sources for this translation done by The National Archives within Portugal-UK 650:

TNA C 76/56, m 17, item 14 (Latin text)

Rymer’s Foedera, original edition, Vol. VII, pp. 15-19 (Transcription)

British and Foreign State Papers. 1812-1814. Vol. I – Part I. (London, 1841), Treaties of Alliance and Commerce between Great Britain and Portugal; subsisting between the Two Powers in 1814., pp. 462-8 (English translation)

Translated by Helen Watt, with many thanks to Dr Shelagh A. Sneddon for all her assistance in revision of the translation.

Downing Street Joint-Declaration 13 June 2022


On 13 June 2022, at Downing Street, the Primes Ministers of Portugal and United Kingdom signed a new agreement. The Treaty of Tagilde, signed on 10 July 1372, is mentioned  in the introduction  and was in exhibition during the signature thus uniting the past, present and the future of the Alliance. You can read the contents of the agreement in: UK-Portugal_Joint_Declaration




The 600 Years of the Alliance

Ratification of the Treaty of Windsor by King John I of Portugal. © Crown copyright. Licensed under the Open Government Licence v3.0. (


In this section, we highlight some of the activities to mark the 600 years of the Anglo-Portuguese Alliance, which were celebrated, both in Portugal and in the United Kingdom.

From 5 to 8 June 1973, HRH the Duke of Edinburgh, Prince Philip visited Portugal. By courtesy of the RTP Archives, we share a series of short reports on different activities that took place during the visit:

06.06. 1973. Lisbon. Banquet at the Ajuda National Palace and visit to the exhibition at the Calouste Gulbenkian Foundation, the School-Ship Sagres and the Ribatejo.

07.06.1973. Prince Philip and his entourage look at a tile panel illustrating the marriage of King John I and Queen Philippa of Lancaster marking the 600th anniversary of the Anglo-Portuguese Alliance, and meet with various persons present in the garden of the residence of the British Ambassador to Portugal, where the official birthday of Queen Elizabeth II was being celebrated.

07.06.1973. Prince Philip visits Lisnave Shipyard and the Manoel de Mello Training Centre

07.06.1973. Sintra. Luncheon in honour of Prince Philip at the Palácio da Vila

07.06.1973. Seixal. Prince Philip visits the facilities of a communications equipment factory in Santa Marta de Corroios.

08.06.1973. Correio-Mor Palace in Loures. Equestrian show in honour of Prince Philip organised by the Portuguese Equestrian Federation

08.06.1973. Belém Palace. Admiral Américo Tomás, President of the Portuguese Republic, received the representative of the Anglo-Portuguese Alliance, who offered him a commemorative medal.

Other commemorative activities of the VI centenary of the Anglo-Portuguese Alliance:

1973: British Institute, Exhibition “British Contributions to the Historiography of Portugal”.

Inauguration on 24.05.1973. Arrival of José Veiga Simão and visit to the exhibition, in the company of David Francis Muirhead, British Ambassador to Portugal

23.05.1973. Lisbon, National Archive of Torre do Tombo. Rui Patrício, Minister of Foreign Affairs, and José Veiga Simão, Minister of National Education, inaugurating the exhibition commemorating the VI Centennial of the signature of the Anglo-Portuguese Treaty of Alliance

23.05.1973: Lisboa, Arquivo Nacional da Torre do Tombo, Rui Patrício, Ministro dos Negócios Estrangeiros e José Veiga Simão, Ministro da Educação Nacional, inauguram exposição documental comemorativa do 6º Centenário da assinatura do tratado de aliança Luso-Britânico

29.05.1973. In Lisbon, former ministers and members of the British Parliament visit the city in an initiative by the House of Portugal in London, with the support of the Secretary of State for Information and Tourism and the Portuguese Old Cars Club, within the framework of the commemorations of the VI centenary of the signature of the Treaty of the Anglo-Portuguese Alliance.

03.12. 1973: British Community in Portugal organises dinner as part of the commemorations of the VI centenary of the Anglo-Portguese Alliance

6.06.1973 to 16.06.1973: Calouste Gulbenkian Foundation, Lisbon

Exhibition of the work of English painter William Turner (1775-1851), displayed for the first time in Portugal as part of the celebrations marking the 600th anniversary of the Anglo-Portuguese Alliance.

A partnership between the Calouste Gulbenkian Foundation, the British Council and the British Museum

United Kingdom:

11.06.1973 – 22.07. 1973. British Museum, London. Historical exhibition commemorating the signing of the treaty of alliance on 16 June 1373: 600 years of the Anglo-Portuguese Alliance

22.06.1973. Plans of horses boarding at Santa Apolónia station for exhibition in Stanley, UK, in the commemorations of the 600 years of the Anglo-Portuguese Alliance.

16.07.1973 – 18.07.1973. Marcelo Caetano’s visit to London 1973

600th anniversary of the Treaty of Windsor:

In 1985, visit of Her Majesty The Queen Elizabeth II and The Duke of Edinburgh to Portugal.

In 1986, His Excellency The President of the Republic of Portugal and the Prime Minister and other Portuguese authorities visited London. The Program included:

-12th May 1986 Service of Thanksgiving to celebrate the 600th anniversary of the Treaty of Windsor.


St George’s Chapel, Windsor Castle. With the presence of Her Majesty The Queen, President of the Republic of Portugal, HRH Princess Anne and other authorities from both countries.

One lesson was read by the Prime Minister of the Republic of Portugal and the other by the Secretary of State for Foreign and Commonwealth Affairs

-Luncheon at Windsor Castle given by Her Majesty The Queen, 12th May

News published in The Times, 13 May 1986 by Nicholas Ashford:

“The Queen and President Soares of Portugal attended a thanksgiving service at St George’s Chapel, Windsor, yesterday to commemorate the 600th anniversary of the Anglo-Portuguese alliance.
At a moving ceremony that drew on the traditions of both lands, the good and the great paid tribute to the wisdom and foresight of King Richard II and King Joao I, who had signed the Treaty of Windsor six centuries earlier.
Although relations between the two countries have had their ups and downs since then, particularly in the I9th century scramble to establish empires in Africa, the alliance has proved itself to be a durable and beneficial bond.
As the Duke of Wellington observed at a reception after the service: ’Although rivals, Britain and Portugal were never enemies and never exchanged a shot between them.’
The service included musical arrangements by a former Portuguese monarch, Joao IV, and the ‘king’ of modern English composers, Sir Benjamin Britten.
One lesson was read in Portuguese by Senhor Anibal Cavaco Silva, the Prime Minister, and the other in English by Sir Geoffrey Howe, the Foreign Secretary.

-Reception at the Portuguese Embassy, 6.30pm given by The President of the Republic of Portugal, 12th May

-Treaty of Windsor Ball, 2nd June 1986, Osterley Park with the presence of TRH The Prince and Princess of Wales. Ball included a performance by the Portuguese Equestrian School accompanied by the Royal Regiment of Wales.

-In 1987 the Princes of Wales visited Portugal, to mark the 600 anniversary of the marriage of King John I of Portugal with Philippa of Lancaster.

In 1987 the Princes of Wales visited Portugal, to mark the 600 anniversary of the marriage of King John I of Portugal with Philippa of Lancaster.




600 years of the Alliance


Minute 2:00 Speech by His Excellency the President of the Republic Américo Tomás
Minute 7:52 Speech by HRH The Duke of Edinburgh, Prince Philip


World War II

The Azores during WWII



Winston Churchill, Speech to the House of Commons, invoking the Anglo-Portuguese Treaty of 1373, 12th October 1943

‘“I have an announcement to make to the House arising out of the Treaty signed between this country and Portugal in the year 1373 between His Majesty King Edward III and King Ferdinand and Queen Eleanor of Portugal. This Treaty was reinforced in various forms by Treaties of 1386, 1643, 1654, 166o, 1661, 1703 and 1815 and in a secret declaration of 1899. In more modern times, the validity of the old Treaties was recognised in the Treaties of Arbitration concluded with Portugal in 1904 and 1914. Article I of the Treaty of 1373 runs as follows:” 

‘In the first place we settle and covenant that there shall be from this day forward … true, faithful, constant, mutual and perpetual friendships, unions, alliances and needs of sincere affection and that as true and faithful friends we 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.’


This engagement has lasted now for over 600 years and is without parallel in world history. I have now to announce its latest application. At the outset of the war the Portuguese Government, in full agreement with His Majesty’s Government in the United Kingdom, adopted a policy of neutrality with a view to preventing the war spreading into the Iberian Peninsula. The Portuguese Government has repeatedly stated, most recently in Dr. Salazar’s speech of 27th April, that the above policy is in no way inconsistent with the Anglo-Portuguese Alliance which was reaffirmed by the Portuguese Government in the early days of the war.

His Majesty’s Government in the United Kingdom, basing themselves upon this ancient Alliance, have now requested the Portuguese Government to accord them certain facilities in the Azores which will enable better protection to be provided for merchant shipping in the Atlantic. The Portuguese Government have agreed to grant this request, and arrangements, which enter into force immediately, have been concluded between the two Governments regarding (1) the conditions governing the use of the above facilities by His Majesty’s Government in the United Kingdom and (2) British assistance in furnishing essential material and supplies to the Portuguese armed forces and the maintenance of the Portuguese national economy. The Agreement concerning the use of facilities in the Azores is of a temporary nature only, and in no way prejudices the maintenance of Portuguese sovereignty over Portuguese territory. All British Forces will be withdrawn from the Azores at the end of hostilities. Nothing in this Agreement affects the continued desire of the Portuguese Government, with which His Majesty’s Government have declared themselves in full sympathy, to continue their policy of neutrality on the European mainland and thus maintain a zone of peace in the Iberian Peninsula.

In the view of His Majesty’s Government, this Agreement should give new life and vigour to the Alliance which has so long existed between the United Kingdom and Portugal to their mutual advantage. It not only confirms and strengthens the political guarantees resulting from the Treaties of Alliance, but also affords a new proof of Anglo-Portuguese friendship and provides an additional guarantee for the development of this friendship in the future. On the conclusion of these negotiations my right hon. Friend the Foreign Secretary, who has, I think, conducted them with the very greatest skill and patience, has exchanged most cordial messages with the Portuguese President of the Council. In his message, my right hon. Friend affirmed his conviction that the facilities now granted by the Portuguese Government would greatly contribute to the effective defence of our shipping and thus prove an important factor in shortening the war. He added that the Agreement would give fresh vitality to the ancient Alliance and enhance the close and friendly relations which have so long subsisted between Portugal and Great Britain. In replying to this message, Dr. Salazar stated that he shared the hope that the facilities granted by Portugal to her Ally would help to bring about greater safety for shipping in the Atlantic and that he trusted that this new proof of Portugal’s loyalty to her traditions would fortify the secular Alliance and serve to draw still closer the bonds of friendship between the two peoples.

I take this opportunity of placing on record the appreciation by His Majesty’s Government, which I have no doubt is shared by Parliament and the British nation, of the attitude of the Portuguese Government, whose loyalty to their British Ally never wavered in the darkest hours of the war.”
In Commons and Lords Hansard, the Official Report of debates in Parliament, ‘Deb 12 October 1943’, vol 392, 716-9.


Oliveira Salazar, Prime Minister of Portugal in response to Churchill, 26th November, 1943

“Salazar said:

…Having considered the matter in all its aspects, the Portuguese Government showed no hesitation in giving the British Government’s request a reply favourable, in principle, and did give this reply without delay. However, the political, military and economic problems arising out of such reply and the corresponding concession of facilities, had quite naturally to be examined and solved.

…The traditional faithfulness of the Portuguese People to their friendships and to the Secular Anglo-Portuguese Alliance has been acknowledged in the House of Commons. It is only fair to concede that, from the outbreak of the war and even during the darkest, and most difficult hours, has Portugal, moved by a sense of honour and self-respect, upheld her loyalty to that alliance in a simple clear way.

… If Brazil, related to us by ties of blood, can reconcile her belligerency with our neutrality without any breach of brotherly friendship, there is no doubt that any change in our position arising from the Anglo-Portuguese Alliance, being also to Brazil’s advantage, could not but deserve increased applause from the Brazilian People.

… As for Spain, in spite of her special attitude towards the conflict and of the demands of her own interests the reaction of the Spanish Government was so understanding, spontaneous, clear and true as if they wanted to surpass themselves in loyalty and transcend Spanish traditional chivalry.

…We have tried, through difficult negotiations not always successful, to safeguard the fundamental interest of our domestic and colonial economy, to assure the minimum for the life of the population and above all to trade with both parts without allowing our economy to serve as an instrument in a war to which we are alien. However, we have at all times reserved the largest share and the United Kingdom.

…The Portuguese People understand from instinct how important is to Portuguese sovereignty in the various parts of the world, even in these unsettled times, such effective unmistakable guarantee received from two of the greatest maritime Powers, allied in war and, associated in peace.

Fonte: In The Anglo-Portuguese Secular Alliance, Sotramel, Lisboa, 1956, 22.

Heads of State


Her Majesty The Queen Elizabeth II


The Queen in her speech of welcome said:

I am most happy, Mr. President, to welcome you and Mme. Craveiro Lopes to London today

My people in the United Kingdom greet you as the Head of the State which has been their friend and ally for over 800 years. We greet you, too, as the representative of a proud people with whom we have, in more recent days, forged new and wider bonds.

The ancient alliance between us is founded on the Treaty, which was signed in this City of London in 1373 and which was confirmed in the Treaty of Windsor of 1386. But our friendship is at least 200 years older than our formal alliance, and began in your country, Mr. President, in a common brotherhood of arms.

Its foundations were laid by those English knights who paused in Lusitânia, on their way in the Holy Land, to help your people free Lisbon from their enemies.

Besides mutual interest, mutual respect and sentiment have been the foundation of our accord. The people of Britain, whose history, like that of your own people, has been moulded by the sea, have always admired the exploits of your sailors and explorers, including the gallant Bartolomeu Dias whose name is borne by the ship which has brought you here today.

The comradeship of the sea is a very real one and it still inspires the traditional cooperation of our merchants and the work of the economic organisations of which we are both members. I hope that our trading partnership, which is as old as our friendship, will long continue to the benefit of our two peoples.

I am delighted that during your visit an exhibition will open in London of the work of Portuguese artists and craftsmen, yet another example of the close and friendly understanding between our countries.

Perhaps the greatest change in these last eight centuries has come from the contraction of the world’s horizons which has made it necessary to organise mankind in the widest possible association of States. The ties between our two countries have in recent years been supplemented by common membership of new organisations of this kind: but these associations like the old, depend upon the confidence and trust of their members, and in this respect the nations have still much to learn from the history of the past.

I think, Mr. President, that our own solid, perpetual and real league provides a striking example of fidelity throughout the years.

Mr. President, I raise my glass to your health and that of Mme. Craveiro Lopes, and to the prosperity and happiness of the people of Portugal.

In The Anglo-Portuguese Secular Alliance, Sotramel, Lisboa, 1956, 11-12.


His Excellency The President of Portugal, General Craveiro Lopes


The President, replying, said:

Madam, my wife and I have been deeply touched by your Majesty’s kind words of welcome, and we feel indeed happy at the truly captivating hospitality you are so graciously extending to us.

I am sure the entire Portuguese people share to the full these sentiments of gratification and of true friendship which have brought us on this visit to our most ancient ally.

It is very true that the ties which, ever since the heroic times of the Crusades and of chivalry, have bound our two countries, provide in the history of the nations, a unique example of good understanding and of constant and fruitful cooperation.

You referred in a most felicitous way, to Portugal’s past as a seafaring nation. I can say that, for our part, we Portuguese also hold in great admiration the maritime role which Britain in turn came to play. It was by covering the Seven Seas that the maritime glory of your country proved of great service to the cause of civilisation through the spreading of those great moral vallues which represent the Western world’s most precious heritage.

The friendship between Portugal and Great Britain has survived the passage of time in all its diversity. In this century, during which Great Britain has twice had to endure suffering surpassed only by her glories, the feelings of the Portuguese people for the British people have never ceased to deepen. Throughout that period our close association has been marked by many memorable events and we are now co-operating in new and important endeavours designed to serve the cause of peace and good understanding among the nations.

With this, there have developed ever closer contacts between us in every field. Our trading partnership is, in fact, as old as our friendship, and in cultural matters as well our relations date from very far back. I, too, earnestly hope that the economic and cultural ties between us will become more and more intense, to the good of our two peoples.

It is certain that only through mutual trust, of the kind that has inspired our own solid, perpetual and real league, are fruitful and lasting results to be expected from the new forms of international cooperation which in our times are being put to the test. May the peoples of the world witness the consolidation of the atmosphere of peace and freedom for which they are yearning.

On your ascending the throne, Madam, the Portuguese people came under the spell of your youthful charm and graciousness. For they were quick to see in you not only the upholder of great traditions rooted in the distant past, but also the herald of a bright promise for the future. I can affirm that Britain’s old friends fully realise all that your youth stands for in the hearts of your peoples.

These, Madam, are my sentiments in raising my glass to your health and that of his Royal Highness The Duke of Edinburgh, and to the prosperity and happiness of the British people.

In The Anglo-Portuguese Secular Alliance, Sotramel, Lisboa, 1956, 17-18.