Prime Minister Theresa May welcomed the Portuguese President Marcelo Rebelo de Sousa to 10 Downing Street on Wednesday, November 16th.
A Number 10 spokesperson commented, "...the Prime Minister welcomed President of Portugal Marcelo Rebelo de Sousa for a bilateral meeting at Downing Street.
"The Prime Minister and President agreed on the deep historical ties between our two countries and that we should strengthen our relationship in the face of new global challenges.
"They discussed the process for the UK leaving the EU and the Prime Minister reiterated that we will be triggering Article 50 by the end of March next year. She said the UK is leaving the EU but not leaving Europe and that we will be approaching negotiations in a spirit of good will and pragmatism.
"Following the meeting the Prime Minister and the President took a few moments to look at the 630 year old Treaty of Windsor provided by the National Archives* for the occasion. They agreed that the Treaty signed between Portugal and the Kingdom of England in 1386 - the oldest diplomatic alliance between England and another country - reflected the enduring and historic friendship between our two nations."
There is one copy of the Treaty in the UK and one in Portugal.
Historian Peter Booker commented: "as for the copy of the Treaty in the UK, in those days, when it took so long to arrange these matters through plenipotentiaries, we find that after the terms had been agreed, a copy of the Treaty would be made at both ends, and signed by the king. Then the signed copy would be sent to the other end, where it would be signed by the other party. Only then would it be considered ratified.
"Which means of course that there are two copies of this Treaty, one in the ANTT (Arquivo Nacional do Torre do Tombo) and one in PRO (Public Record Office). The one in ANTT is catalogued 'Pergaminho com falta do selo pendente' (parchement missing the official seal)."
The Treaty of Windsor is the diplomatic alliance signed between Portugal and England on 9 May 1386 at Windsor and sealed by the marriage of King John I of Portugal (House of Aviz) to Philippa of Lancaster, daughter of John of Gaunt, 1st Duke of Lancaster.
With the victory at the Battle of Aljubarrota, John I was recognized as the undisputed King of Portugal, putting an end to the interregnum of the 1383–1385 Crisis. The Treaty of Windsor established a pact of mutual support between the countries.
