The Treaty of Windsor, 1386: Portugal and England's perpetual league

On 9 May 1386, in the castle of Windsor, a doctor of laws named Richard Ronhale set out 'in a loud and clear voice', before all present, the terms of an alliance between Richard II of England and João I of Portugal. That is how Fernão Lopes, Portugal's royal chronicler, told it half a century later. He placed the castle seven leagues from London, and said three bishops and the king's uncle, the Duke of York, had been called in to hear it.2 sources2 sources

The parchment itself survives. Its list of witnesses names William, Bishop of Winchester, John, Bishop of Durham, Edmund, Duke of York, the earls of Salisbury and Northumberland, and Sir Simon Burley, the king's under-chamberlain. On the Portuguese side stood Fernando Afonso de Albuquerque, Master of the military Order of Santiago, and Lourenço Anes Fogaça, chancellor of Portugal. The notary who drew it up, John de Bouland, recorded that it was done in the chapter house of the royal chapel below the castle. The envoys' two seals still hang from the foot of the sheet.4 sources4 sources

The two men had been in England for more than a year, raising soldiers and loans for a king whose crown was barely a year old. What they sealed that day was a perpetual league. Each king would help the other against anyone who attacked him, and their subjects could trade and settle in each other's countries as freely as at home.3 sources3 sources

The alliance it confirmed has never been ended. Britain and Portugal call it the oldest diplomatic alliance in the world still in force, and date it from an earlier treaty of 1373. The National Archives in London, which keeps both documents, says the one sealed at Windsor helped turn a fledgling alliance into a lasting one.3 sources3 sources

In the 1370s and 1380s England was fighting the Hundred Years War with France. In 1369 France allied with Castile, the largest kingdom in Spain, whose fleet was one of the largest in western Europe. English strategists looked for a way round it, and found one on Castile's western border: Portugal.1 source1 source

There was a family stake too. King Pedro of Castile had been killed in 1369, at war with his half-brother Enrique of Trastámara, who took his throne with French support. In 1371 John of Gaunt, Duke of Lancaster and son of Edward III of England, married Pedro's daughter Constance, and from then on called himself King of Castile in her right.3 sources3 sources

Portugal's King Fernando I was at war with Enrique as well. On 10 July 1372, at the church of São Salvador de Tagilde in the Minho, he made a treaty with Gaunt's envoys to fight Castile together. His ambassadors then went to London, and on 16 June 1373, at St Paul's Cathedral, they agreed a treaty of perpetual friendship and alliance with Edward III. One of them was João Fernandes Andeiro, the Galician knight whom João of Avis would kill in Lisbon ten years later.3 sources3 sources

The friendship soon soured. In 1381 and 1382 an English army under Gaunt's brother Edmund, Earl of Cambridge, came to Portugal to fight Castile. Its undisciplined troops raided Portuguese towns and killed their people, and in 1382 Fernando made peace with Castile, leaving the English out of the talks.1 source1 source

Then the Portuguese crown itself was in play. Fernando died in October 1383, leaving an only daughter, Beatriz, married to Juan I of Castile. Lisbon rose for João, Master of the Order of Avis, Fernando's illegitimate half-brother. The Cortes of Coimbra proclaimed him king on 6 April 1385, and on 14 August that year his army beat the Castilians at Aljubarrota. Each of those episodes has its own Lisboeta article.2 sources2 sources

João had sent envoys to England in December 1383, within weeks of taking power in Lisbon. Richard II let them hire men-at-arms and archers in his kingdom. On 15 April 1385, nine days after the Cortes made him king, João gave the Master of Santiago and Fogaça new powers at Coimbra: to make an alliance with Richard II and with John of Gaunt, and to borrow money in England to pay his troops.4 sources4 sources

That commission, sealed with João's lead seal, is still at Kew. Among the witnesses at Coimbra was João das Regras, the lawyer who had argued João's case before the Cortes. The money came slowly and at a price. On 16 April 1386 the envoys signed a bond to repay £1,000 lent to the King of Portugal by Sir Thomas Moreaux, Sir Henry Grene and other London merchants, and in 1404 Henry IV had to promise Portuguese traders they would not be harassed over debts the two envoys had left behind.5 sources5 sources

England took its time. According to The National Archives, the turn came in early 1386, when a French and Castilian invasion of England looked likely and Gaunt began planning a summer expedition to Castile. For that he would need Portuguese help.1 source1 source

Lopes gives the moment a family scene. When the Master of Santiago called on the duke, Constance and her daughter Catherine wept and begged him to win back the kingdom that was theirs by right; the Master told Gaunt that the ladies' request was entirely reasonable. Gaunt promised to go. He then laid his case before the king and council, who gave him leave, and decided that a firm alliance with Portugal had to come first.1 source1 source

On 28 April 1386, at Westminster, Richard II sealed a treaty of perpetual alliance with Gaunt himself as King of Castile and León. Eleven days later the Portuguese treaty followed at Windsor. Gaunt's biographer Sydney Armitage-Smith, writing in 1904, called the Portuguese alliance 'the Duke's own creation'.2 sources2 sources

The treaty is written in Latin as a notarial instrument issued by the two Portuguese envoys. It records that they had negotiated 'after various sittings' with Richard II's commissioners: two knights, Sir Richard Abberbury (spelt Atterbury in the printed text) and Sir John Clanvowe, and Master Richard Ronhale, doctor of laws, the man Lopes has reading it aloud.3 sources3 sources

Its first article set up a league between the two kings, their heirs, successors and subjects, to last for ever. It named three exceptions: Pope Urban VI, Wenceslas, King of the Romans and of Bohemia, and, on England's side only, John of Gaunt as King of Castile.3 sources3 sources

The papal exception mattered. The Church then had two rival popes. England and João's Portugal obeyed Urban VI in Rome, while Juan I of Castile followed the pope at Avignon, and Urban granted indulgences to those who joined Gaunt's expedition. The treaty's preamble praised kings who stood together 'in true unity and obedience' to the Roman Church.3 sources3 sources

The trade and residence article went further than the treaty of 1373, which had dealt with friendship, enemies and military help. It was used. The National Archives notes Portuguese records of English cloth and other goods passing through Porto, and 20 people identified as Portuguese in English tax lists of aliens from the 1440s.2 sources2 sources

The envoys signed a second document at Windsor the same day. In it they undertook, on João's behalf, to supply ten vessels for Richard II's use during the coming summer. The National Archives describes them as galleys to be stationed in English waters to protect English shipping and the south coast, a sign that João meant to be a useful ally.3 sources3 sources

At Windsor the envoys swore on the Gospels, in their king's name, to keep the league. The business did not end there. The notary's record goes on to a second sitting on 17 May, in the Star Chamber of the palace of Westminster, and Armitage-Smith dates the conclusion of the treaty to both days.2 sources2 sources

Ratification took longer. The National Archives says the English ratification was enrolled on the Treaty Rolls on 1 December 1386, though a later English copy, listed in Thomas Duffus Hardy's 1873 guide to Rymer's Foedera, dates Richard II's ratification at Westminster to 24 February 1387. João I approved the treaty 'with royal mouth' and swore to it on the Gospels in his palace at Coimbra on 12 August 1387, and sent it to England under his lead seal. That document is at Kew too, as E 30/311.4 sources4 sources

Portuguese ships were already on their way. On 30 June 1386, by Armitage-Smith's account, João's admiral Afonso Furtado reached Plymouth with ten galleys and half a dozen smaller ships for Gaunt's use, help that Armitage-Smith counts as separate from the naval force the envoys had promised Richard II. Lopes has Furtado landing first in Cornwall. Gaunt sailed on Sunday 7 July, turned aside to relieve the English garrison besieged at Brest in Brittany, and came into Corunna, in Galicia, on 25 July, the feast of Santiago.2 sources2 sources

He brought his wife Constance and his two unmarried daughters, Philippa and Catherine. Nobody knows exactly how many soldiers came with them, and the chroniclers disagree widely.1 source1 source

On 1 November 1386 Gaunt and João met at Ponte do Mouro, on the Minho border, and agreed a joint invasion of Castile. João also chose one of the duke's daughters as his bride, and on 2 February 1387 he married Philippa of Lancaster in Porto cathedral, with the public feast on 14 February, a story told in Lisboeta's article on the queen.2 sources2 sources

The campaign of 1387 failed. Disease swept through the English army that summer, killing lords, knights and great numbers of archers, while the Portuguese troops were spared. João told Gaunt he must either raise a new army in England or accept the terms Castile was offering. At Trancoso, in Portugal, the duke accepted them.1 source1 source

The final treaty, agreed at Bayonne in 1388, was generous to the loser. Gaunt and Constance gave up their claim to Castile. In return Juan I agreed to pay 600,000 gold francs in instalments over three years and an annuity of 40,000 francs for their lifetimes, and Catherine of Lancaster married Juan's heir Enrique. Armitage-Smith made her fourteen, but the historian Óscar Villarroel González dates her birth to the late spring of 1372, which made her sixteen. Philippa became Queen of Portugal and her half-sister, in time, Queen of Castile.2 sources2 sources

For England, The National Archives notes, the strategic reason for the alliance had gone, and it was sidelined for a time. What kept it alive was Philippa's marriage, which tied it to the English royal family, and the trade that the treaty protected.1 source1 source

Later kings did renew it. Gaunt's son, who became Henry IV of England in 1399, confirmed the treaty 'dated 9 May 1386' in 1404, and when João I died his son and successor Duarte promised to keep his father's treaties with England. In 1400 João I became the first foreign monarch made a Knight of the Garter.3 sources3 sources

Later treaties wrote the old promise into new circumstances. In 1642 Charles I and João IV agreed that neither would join any war or treaty against the other; the marriage treaty of Charles II and Catherine of Braganza in 1661 added a secret promise to defend Portugal's colonies; and in May 1703, during the War of the Spanish Succession, Portugal signed treaties of alliance with England and the Dutch Republic.3 sources3 sources

Then it was invoked in war. In 1762 British and Portuguese troops drove back a Spanish invasion. In the Peninsular War an Anglo-Portuguese army under Wellington, about 50,000 strong, held Bussaco ridge against some 65,000 French troops on 27 September 1810. In 1916 Portugal's minister in Washington said his country had been drawn into the First World War by its alliance with England.2 sources2 sources

In October 1943 Winston Churchill told the House of Commons that Britain, basing itself on the ancient alliance, had asked neutral Portugal for facilities in the Azores, and Portugal had agreed. In 1982, during the Falklands War, Portugal agreed in principle to let an RAF Nimrod stage through Lajes in the Azores up to once a day.3 sources3 sources

The National Archives calls the alliance a valid agreement still endorsed by both countries, and the British government describes it as the oldest diplomatic alliance in the world in force. The two countries are now also NATO allies.2 sources2 sources

On 16 June 2023 the two states marked 650 years since the 1373 treaty with a service at the Queen's Chapel in London, attended by King Charles III and Portugal's president, with an original of the 1373 treaty lent by The National Archives. 'No other relationship on the planet has survived the test of time as well as ours,' said the Foreign Secretary, James Cleverly.1 source1 source

For Portugal the treaty had a more immediate meaning in 1386. A king who had won his throne by revolt and battle had English archers in his army and loans from London merchants, and he married into England's royal family. The alliance gave the new House of Avis a powerful friend while the war with Castile dragged on; a final peace was signed only in 1411.3 sources3 sources